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Answers to House of Wisdom questions
English
Why does a tiger have streaks on its body?1.They have no purpose aside from
making the tiger look beautiful. 2. They are the best protective color for the
tiger.3.They distinguish the male from the female.Key ExplanationЈєThe tiger
usually lives in grassy or forested areas. In order to adapt its color to its
surroundingsЈ¬ its hair color and streak gradually become the "protective
color".Correct Answer: 2
How does a lion mark its territory?1.By marking it with fixed objects.2.By means
of urinating. 3.By distinguishing it with signals.Key ExplanationЈєUsuallyЈ¬ a
group of lions is composed of several mature male lionsЈ¬ and a majority of
female and little ones. The male lions will set their sphere of influence by
means of urinating in order to protect others in their group from outside
invasion.Correct Answer: 2
How successful is the lion when hunting?1.It is successful one out of seven
times.2.It is successful every other time.3.It is successful one out of five
times.Key ExplanationЈєThe lion is probably the best hunter in the animal world.
It is successful once in five times while hunting. SoЈ¬ after catching something
edibleЈ¬ it usually eats to satiation to prevent hunger in time of food
shortage.
It can eat nothing for about a week after fully eating.Correct Answer: 3
Is the elephant really afraid of the little mouse?1.It is not afraid of the
mouse
at all.2.It loathes the noise made by mouse.3.It is in fact afraid of small
animalsЈ¬not just the mouseЈ¬ entering its body.Key ExplanationЈєBecause of its
huge body and large body cavitiesЈ¬ the elephant will feel pain if small animals
enter into its body. Any incursion of foreign matter will cause it to
suffer.Correct Answer: 3
Why doesnЎЇt the elephant choke when it uses its trunk to drink water?1.Because
its trachea doesn't connect with its gullet.2.Its trachea connects with the
gulletЈ¬ but between them a cartilage valve can open or close at any time.3.Its
trachea connects with its gulletЈ¬ but its lungs can close temporarily. Key
ExplanationЈєThe trachea and gullet of the elephant are connected to each
otherЈ¬
but there is a cartilage valve on top of the gulletЈ¬ which will cover the
trachea when the elephant drinks water. Thus the water will not enter into its
trachea.Correct Answer: 2
What does an elephant do before it relieves itself?1.It lifts its leg like a
dog.2. It digs a hole.3.It raises its tail.Key ExplanationЈєThe elephant is very
fond of cleanlinessЈ¬ it doesn't want to make its tail and legs dirty while
relieving itself. Before emptying its bowels it will raise its tail. Before
urinating it will separate its hind legs.Correct Answer: 3
Why does the boar have long and sharp teeth?1.They are used as a weapon to
resist
the enemy.2.They are used to look for food.3.They help in chewing food.Key
ExplanationЈєWhen in an emergencyЈ¬ the boar will lower its headЈ¬wave it back
and
forthЈ¬ and rush straight forward. At that timeЈ¬ its long and sharp teeth
become
an effective weapon.Correct Answer: 1
Why do quills grow all over the body of the porcupine? 1. 1.The quills make
the porcupine look beautiful.2. 2.The quills help the porcupine to resist its
enemies. 3. 3.The quills can be used by the porcupine to prey on little
animals.Key Explanation: The quills on the body of the porcupine grow from its
mane. They are an effective weapon when defending against the attack of an
enemy,
it erects its quills with a "zip" to stand to threaten them.Correct Answer: 2
Can bears climb trees?1. They can't at all.2. Some can , others can
not.3. They are good at climbing trees , but seldom do because of their heavy
weight.Key ExplanationЈєBears are skillful at climbing treesЈ¬ but they seldom
do
because of their heavy weight. Only little ones like doing it. SoЈ¬ upon meeting
a bear it isnЎЇt necessarily safe to climb a treeCorrect Answer: 3
Why doesnЎЇt a polar bear slip when walking on ice?1.The acetabulum on its soles
can absorb the ice.2.The caruncle on its soles functions like a spike.3.Its
soles
are full of hairЈ¬ which can keep it warm and help prevent slipping.Key
ExplanationЈєThe polar bear has a dense clump of hair on its sole. It can run as
well on ice as on landЈ¬ without fear of slipping.Correct Answer: 3
Is a raccoon baby different from its parents? 1.The only difference is in
size.2.The only difference is in color.3.The raccoon baby has no black spots
around its eyes.Key ExplanationЈєThe biggest difference between a raccoon and
its
baby is that there are no black spots around the babyЎЇs eyes. In additionЈ¬ a
raccoon baby canЎЇt open its eyes until 26 days after birth.Correct Answer: 3
Why does the raccoon wash its hands before eating?1.It washes its hands because
it likes cleanliness.2.It washes its legsЈ¬ not its hands.3.It looks for food in
water instead of washing its hands.Key ExplanationЈєThe front legs of the racoon
are very sensitive. It knows whether food is edible or not as soon as it touches
it. Its main foods are fishЈ¬ shrimpЈ¬ and crab. SoЈ¬ it always looks for food
in
water.Correct Answer: 3
How can a koala sleep in a tree without fear of falling out?1.It can find stiff
branches and support its body with its hind limbs.2.It stands on a branchЈ¬
embracing it tightly.3.Something like suction cups on the soles of its feet can
grip the tree. Key ExplanationЈєThe koala bear eats only the leaves of the
eucalyptus tree. When sleepingЈ¬ it embraces the branch with its four limbsЈ¬
holding on especially tightly with the soles of its feet. Thus it will certainly
not fall down.Correct Answer: 2
How is the baby pouch of the koala bear different from the kangarooЎЇs?1.It will
not harm the baby when climbing trees.2.Its baby can enter in and out freely.3.
It can not be found by the enemy.Key ExplanationЈєThe koala bear not only eats
leavesЈ¬ but it also lives in tree holes. Its baby-pouchЈ¬ unlike that of the
kangarooЈ¬ faces down to protect the baby from being bumped when the koala bear
climbs up and down trees.Correct Answer: 1
Does the koala bear have a tail or not?1.Its name comes from the fact that it
has
no tail.2.The majority of koala bears have no tailЈ¬ only a few of them have a
tail.3.It has a tailЈ¬ but it is too small and short to be seen.Key
ExplanationЈє
In factЈ¬ koala bears have a tail. But the tail is too small and short to be
seen.Correct Answer: 3
Where does the horn of the rhinoceros come from?1.It is hair that hardens to
form
the horn.2.It is related to its genetics.3.Its nose changes into a horn.Key
ExplanationЈєThere are many kinds of rhinoceros. Only the Java rhinoceros has a
big-head horn. All the rest have two horns. In factЈ¬ the horn grows from hair
without marrow. It is the rhinocerosЎЇ weapon.Correct Answer: 1
Why do rhinoceroses and elephants smear mud on their bodies? 1.They don't like
cleanliness.2.To avoid evaporation of moisture and drive away insects.3.They are
taking a bath.Key ExplanationЈєMost rhinoceroses and elephants live in tropical
areasЈ¬ they like taking a bath in water frequently to cool themselves. They
smear mud onto their bodies to make a protective film after bathing and to avoid
the evaporation of moisture. At the same timeЈ¬ it can protect against the bites
of lice and insects.Correct Answer: 2
Why are hippopotamuses always bathing in water?1.Because they want to make sure
that their skin doesnЎЇt become too dry.2.Because they are afraid of the heat.
Bathing in the water is much cooler.3.It is easier for the hippopotamus to move
its large body while in the water.Key ExplanationЈєThe skin of the hippopotamus
is between two and three centimeters thick. It dries out very easily. In order
to
prevent this from happeningЈ¬ the hippopotamus must soak itself for long periods
of time. A layer of mucus protects the hippopotamusЎЇ skin.Correct Answer: 1
Why does the zebra have black and white stripes?1.They can confuse the eyesight
of the zebrasЎЇ enemy.2.The stripes can alarm other animals.3.It has no use but
it
is a genetic characteristic.Key ExplanationЈєThe streaks on the body of the
zebra
are a kind of protective adaptation. In the bright sunshineЈ¬ they can destroy
and decentralize the outline of the zebraЎЇs body. It is difficult to
distinguish
it clearlyЈ¬ which can help it to avoid attack.Correct Answer: 1
Why does the giraffe seldom drink water?1.It can store water like a camel.2.Its
main food is abundant in moisture.3.Because it has adapted to an arid
climate.Key
ExplanationЈєThe giraffe is able to live in arid places because it eats tender
leaves and sprouts filled with moisture.Correct Answer: 2
Why does the giraffe sleep standing up?1.ActuallyЈ¬ most giraffes lie down to
sleep.2.They sleep standing up in order to defend themselves from their
enemy.3.ItЎЇs hard work for them to lie down and then stand up.Key ExplanationЈє
The giraffe has no ability to struggle with its enemy. It can only run away as
soon as it sees the enemy. So it has to keep standing in order to get ready to
run away at any time.Correct Answer: 2
Why is the neck of the giraffe particularly long?1.It looks beautiful and is
attractive to the opposite sex.2.The giraffe needs a long neck in order to eat
the tender leaves and buds on trees.3.The giraffe needs a long neck in order to
match its long legs and keep balance.Key ExplanationЈєThe long neck of the
giraffe can be used to easily reach the tender leaves and buds on trees. This is
the result of the giraffeЎЇs adapting to its environmentCorrect Answer: 2
Does a panda have six fingers?1.The sixth finger is a fleshy pad.2.The sixth
finger is a protruding bone.3.The panda is a kind of animal with six fingers.Key
ExplanationЈєThe panda uses its five fingers and the protruded fleshy pad to
clip
the bamboo leaves and branches. As with humansЈ¬ its fingers will twist to the
inside when holding something.Correct Answer: 1
Does the panda belong to the cat family or the bear family?1.It belongs to the
panda family.2.It belongs to the bear family.3.It belongs to the cat family.Key
ExplanationЈєThe panda is a special rare carnivorous animal only living in
eastern Asia. Pandas only live in mountainous areas of Sichuan province and
Tibet. At presentЈ¬ zoologists classify pandas in the "panda family".Correct
Answer: 1
Why canЎЇt the panther run for long distances?1.ItЎЇs not necessary for it
because
it can pray on objects easily.2.Its paws protrude forwardЈ¬ so it can run fast
only for a short distance.3.It has weak physical power and endurance. Key
ExplanationЈєThe panther is the fastest animal. It can reach a speed of 110
kilometers per hour. Because of its protruded pawsЈ¬ it can only run for a short
distance despite its high speed.Correct Answer: 2
Where does the leopard hide its leftover food?1.It puts it into a tree2.It
throws
it away.3.It buries it temporarily.Key ExplanationЈєThe leopard is able to put
the dead body of the antelopeЈ¬ which weighs more than the leopardЈ¬ into a
tree.
Being hung in the tree in the shape of a "v"Ј¬ the antelope will not be eaten by
other animalsЈ¬ such as the mane.Correct Answer: 1
Why does the orangutan make a fist when walking?1.So it can attack its enemy at
any time.2.So it can carry something when walking.3.So it can walk quickly.Key
ExplanationЈєThe orangutan holds its fist close to the ground when walkingЈ¬
thus
it can carry objects at any time.Correct Answer: 2
Why is the tail of the kangaroo also its fifth foot?1.It can help to support the
weight of its body independently.2.It can help the hind feet to support its
body.3.It can help the front feet to support its body.Key ExplanationЈєThe
kangaroo is good at jumpingЈ¬ howeverЈ¬ its four feet can not alternate their
steps. When movingЈ¬ its hind feet and front ones step out
simultaneously.Correct
Answer: 2
Do the scales of the pangolin have any use?1.They help the pangolin to stay
warm.2.They prevent too much moisture from entering the pangolinЎЇs body.3.They
are the best protective color and material.Key ExplanationЈєThe pangolin looks
like a pinecone when it is curled up. The stiff and big scales outside the
pinecone are the best protective color and material. The scales look like
withered leaves when the pangolin is on the tree or in the brushwood.Correct
Answer: 3
How does the antelope inform its partner of its location?1.By urinating.2.By
crying.3.By an excretion from under its eyes.Key ExplanationЈєThere is a kind of
gland under the eyes of the antelopeЈ¬ which can excrete a substance with a
special smell. The antelope smears the excretion on trees to tell others its
location and situation.Correct Answer: 3
Which part of the body does the deer use to struggle with its enemy?1.The horns
on the head.2.It kicks its enemy with its strong hind legs.3.It cries loudly to
frighten its enemy.Key ExplanationЈєDeer seldom struggle with others. Only
during
the mating season will male deer fight over female deer. They use their horns as
weapons.Correct Answer: 1
How does a beaver alert other beavers in the event of danger?1.It communicates
with other beavers directly using sounds.2.It claps the water in an effort to
sound the alarm.3.As a social animalЈ¬ beavers alert one another to danger by
clapping each other.Key ExplanationЈєThe beaverЎЇs tail can help it to swim and
change direction. When in dangerЈ¬ its tail will clap the water forcefully Ј¬
making great noise to warn other beavers near by.Correct Answer: 2
Why do beavers build dams?1.They can easily check on the water level at the
mouth
of their den and build the dam.2.Building the dam can supplement the beaverЎЇs
water supply.3.In order to conceal the mouth of its den in waterЈ¬ it builds the
dam to keep the water level.Key ExplanationЈєBeavers usually make their dens in
rivers and marshes. They set the mouth of their den in the water in order to
avoid discovery by their enemy. So they must keep the water level
constant.Correct Answer: 3
Why donЎЇt beavers drown in water? 1.They do not stay a long time in the
water.2.Skin on the beaverЎЇs cheeks prevent water from entering its
mouth.3.They
can stop breathing for a long time.Key ExplanationЈєMost of the body structures
of the beaver are formed due to long-term life in the water. If holding twigs in
the mouthЈ¬ the skin on the cheek can prevent its mouth from taking in water.
When divingЈ¬ there are gristles both in the nose and eyes to avoid the entry of
water. Smear grease excreted around the beaverЎЇs anus can keep its hair dry. So
the beaver can not drown or freeze to death.Correct Answer: 2
How does the sea otter eat the meat inside a shell?1.It can easily bite though
the shell with its stiff teeth.2.It carries the shellfish onto the beachЈ¬ and
it
lets them open in the sunshine.3.It can break the ligaments of shellfish by
using
its sharp teeth.Key ExplanationЈєWhen eating shellfishЈ¬ the sea otter can break
the shell with its teeth or by beating two shellfish together. SometimesЈ¬ it
holds a stone on its chest to break the shell.Correct Answer: 1
How does the skunk protect itself?1.It climbs a tree when in danger.2.Other
animals don't want to approach it at all because of its stench.3.It can send out
a disgusting odor to frighten its enemy.Key ExplanationЈєThere is a kind of
gland
under the tail of the skunkЈ¬ which can excrete liquid. When in dangerЈ¬ it can
send out a repulsive smell in order to help it escape.Correct Answer: 3
Why is the duckbilled platypus considered to be a mammal even though it lays
eggs?
1.Because it lives most of its life in the waterЈ¬ it canЎЇt give birth to its
young like other mammals.2.Like a kangarooЈ¬ it fosters its baby in its
belly.3.The egg is a kind of film to protect the baby.Key ExplanationЈєThe water
living duckbilled platypus of Australia is the most unusual mammal. It produces
eggs, which hatch after a period of ten days. It will also go though a period of
lactation. So it is regarded as a mammal.Correct Answer: 1
English
Why does a dog pant on a hot day?1.ItЎЇs a habitual action.2.It means it is
thirsty.3.It can help in radiating heat.Key ExplanationЈєA dog can not perspire
because it lacks sweat glands and pores on its skin. But there are a lot of
sweat
glands and pores on its tongue. So on hot daysЈ¬ dogs begin panting immediately
in order to help in radiating heat.Correct Answer: 3
How does a dog express its emotion?1.By the action of its four limbs.2.By using
its tail to express its feelings.3.Showing it is afraid by instantly barking.Key
ExplanationЈєThe dog shows its feelings mainly by the action of its tail. When
it
is confident Ј¬ it will clip its tail to be docile; and when it gets ready to
attackЈ¬ its tail will flex into an certain angle.Correct Answer: 2
Why is the tip of a dogЎЇs nose always wet?1. Because dogs lack sweat glandsЈ¬
theydepend upon their noses to help radiate heat.2.It must secrete mucus to
moisten its olfactory cell.3.If a dogЎЇs nose becomes dryЈ¬ it means the dog is
thirsty.Key ExplanationЈєA dogЎЇs nose has a lot of olfactory cells. It should
always secrete mucus to keep the nose moistЈ¬ thus it can transmit all kinds of
olfactory information to the brain.Correct Answer: 2
Why does a dog start barking after it hears the sound of a harmonica?1. It is
extremely sensitive to the sound of a harmonica and barks in enjoyment. 2.It
will bark after hearing sounds of higher frequency.3.It barks in alarm as soon
as
it hears a sound.Key ExplanationЈє The high frequency sound of a harmonica is
similar to the sound of a dog. So dogs canЎЇt help barking as soon as hearing
the
high frequency sound.Correct Answer: 2
Can circus puppies really add and subtract numbers?1.They can make out the
answer
using hints from their owner.2.Because the questions are all the sameЈ¬ they can
remember the right answers.3.They can understand numbers after being trained for
a long time.Key ExplanationЈєAfter being trained for a long timeЈ¬ the puppies
know how many times they must bark at which number with a certain action. So
they
bark at the sight of the numbers.Correct Answer: 3
Why doesn't a dog bark when looking into the mirror?1.Because barking is used to
alert others.2.Because it can not smell any scent.3.It dares not bark after
being
frightened.Key ExplanationЈєBecause of its very sensitive noseЈ¬ a dogЎЇs sense
of
smell is better than its eyesight. So when looking into the mirrorЈ¬ it is
surprised to smell nothing. It will not bark if it thinks there is nothing
around
it.Correct Answer: 2
Why does the wolf like to howl at night?1.In factЈ¬ it howls both in the day and
at night.2.It's the cry of an alert guard-wolf.3.Because the wolf is usually
active at night.Key ExplanationЈєWolves always move at nightЈ¬ looking for food.
They gather together by howling.Correct Answer: 3
Do a catЎЇs whiskers have a special function?1.They can clear away obstacles
that
may be in front of the cat as it moves.2.They can feel for the existence of
other
animals at night.3.They can detect obstacles around the catЈ¬ even in the
dark.Key ExplanationЈєThe catЎЇs whiskers can detect obstaclesЈ¬ letting it know
when to jump instead of pacingЈ¬ and how to move back and forth between two
objectsЈ¬ etc. Without whiskersЈ¬ the cat would have problems moving. For these
reasonsЈ¬ whiskers are very important to the cat.Correct Answer: 3
How is the cat able to jump down from a high place without being injured?1.With
four robust legsЈ¬ it is not easy for it to be injured.2.Because it has soft
muscles to protect itself.3.Because it has an excellent sense of balance.Key
explanationЈєThe cat is good at jumping and climbing. When falling down from a
high place Ј¬ it can quickly balance its body in order to land safely.Correct
Answer: 3
Why does a catЎЇs hair stand on end when it is angry?1.It does this in order to
frighten its enemy.2.It does this because of fear.3.Its hair is a kind of
weapon.Key ExplanationЈєThe cat wants to look more intimidating before a
struggle. All of its body hair stands on end to make itself look bigger. When it
comes across its enemyЈ¬ its skin will become tautЈ¬ enabling its hair to become
erect.Correct Answer: 1
Why does the male cat sing to the female one?1.Because the male cat is afraid of
the female one.2.Because the male cat wants to show its love for and attract the
female cat.3.To frighten the female one.Key ExplanationЈєAll animals can make
criesЈ¬ most of which express hunger or danger. The cry of the male cat is
especially strange and high because it is used to find a partner to mate. The
soundЎЇs purpose is to attract female cat.Correct Answer: 2
Why is the ox always chewing?1. Because it chews the cud.2. In order to keep its
teeth healthy.3.The ox must masticate grass for a long time because of the great
amount of fiber in itKey ExplanationЈєThe ox is a ruminated animal with four
stomachs. It can repeatedly chew the cudЈ¬ letting food into different stomachs.
ThatЎЇs why it is always chewing.Correct Answer: 1
Will the ox be angry at the sight of red?1. The ox becomes angry at the sight
of something wavingЈ¬but in fact it canЎЇt distinguish colors.2. The color red
can
arouse in the ox a of strong consciousness of danger3. The ox is angered because
it sees the keen sword in the hand of the matador.Key ExplanationЈєThe ox canЎЇt
discern colors. Waving anything before it will arouse in it a strong
consciousness of dangerЈ¬ then it will rush to the object excitedly. The matador
uses red cloth only to attract the audienceЎЇs attention.Correct Answer: 1
Do the teeth of a horse have any relationship to its age?1.YesЈ¬ they grow in
length and number as the horse ages.2.There is no particular
relationship.3.YesЈ¬
as the horse grows taller its teeth will grow longer.Key ExplanationЈєHorse Ј¬
oxenЈ¬ sheep and deer are all herbivorous animals. The biggest difference
between
the horse and the rest is that the number of teeth that a horse has increases
with its age. A horseЎЇs teeth will not stop growing until it is five years
old.Correct Answer: 1
Why does the horse often wave its ears?1.The horseЎЇs ears are the organs best
suited to express emotion.2.The ears are used to drive away the annoying
mosquitoes around the horseЎЇs head.3.They are used to help radiate heat.Key
ExplanationЈєBesides being used to hearЈ¬ the horse uses its ears to express all
kinds of emotions. We can tell the feelings of a horse by watching its
ears.Correct Answer: 1
Can an old horse really tell directions?1.It can recognize the way home by using
its sense of smell.2.Its capability of memorizingЈ¬ discerning directionsЈ¬ and
judging is better than other animals.3.It makes marks along the road by
urinating
to find the right way. Key ExplanationЈєCompared with other animalsЈ¬ the horse
has a strong capacity for memorizingЈ¬ discerning directionsЈ¬ and judging. It
can
recognize the road that it has passed through easily.Correct Answer: 2
Does the camelЎЇs hump have a special function?1.It stores fatЈ¬ which is
important in helping the camel to live in the desert.2.It has no particular
function.3.The camelЎЇs stomach is in the hump.Key ExplanationЈєIt is not easy
for
a camel to find food in the desert. Its hump is able to store fat for long
periods of time. ThatЎЇs why the camel can live for a week without eating
anything.Correct Answer: 1
How does the camel find water in the desert?1.It can see the water source with
its good eyesight.2.It can remember the places where it has drunk water in the
past.3.Its olfactory cells can smell water.Key ExplanationЈєA lot of olfactory
cells are distributed in the muscles of the camel. They can be used to look for
the food and water. They can detect moisture even over a long distance.Correct
Answer: 3
Why doesnЎЇt the camel sweat?1. Because it has no sweat gland.2.Its temperature
will increase with the air temperature.3.Its sweat gland has degenerated after
adjusting to life in the desert.Key ExplanationЈєThe camel does not sweat on hot
days. This is in fact related to its temperature. Its temperature changes in the
morning and at night. It sweats less at night because of the high temperature.
This helps to lessen moisture loss from the inside of the camelЎЇs body.Correct
Answer: 2
Why isnЎЇt the camel afraid of sand blown by the wind?1.Because of the dense
hair
on its body. 2.Because its tear gland is developed.3.Because its eyelashes and
nose are very effective.Key ExplanationЈєThere is valve-like organ in the nose
of
the camelЈ¬ which can open and close the nose to resist the sand blown by the
wind. Its double decked eyelashes can easily prevent sand from entering its
eyes.Correct Answer: 3
Can mules have a baby?1.Mules are infertile because they are mixed-blood
animals.2.Mules can't mate because their sex is unclear.3.Mules can have a
babyЈ¬
but they donЎЇt become pregnant easily. Key ExplanationЈєMules are the hybrid
strain of a horse and donkey. Lacking a certain kind of hormone in its
reproduction systemЈ¬ the male mule can't fertilize the femaleЎЇs eggs and they
will quickly die. So mules canЎЇt reproduce.Correct Answer: 1
Why do monkeys often imitate others?1.To show hospitality.2.Imitating others is
an inherent characteristic of monkeys.3.It shows that they are docile
animals.Key
ExplanationЈєGorillasЈ¬ who are the cleverest animals in the monkey categoryЈ¬
and
whose intelligence is first class among animalsЈ¬ have the ability of
recognizing
and learning. For this reason it is easy for them to imitate others.Correct
Answer: 2
Why do monkeys help pick lice off of each otherЎЇs bodies?1.They arrange each
otherЎЇs hair to show intimacy.2.They are getting rid of dirt.3.Monkeys of a
lower
class must pick lice off the bodies of those of a higher class.Key ExplanationЈє
There are no lice on the bodies of monkeys. They in fact arrange each otherЎЇs
hair to show intimacy. Only those without hostility will do it.Correct Answer: 1
How is the monkey king chosen?1.He is chosen hereditarily.2.He is the one who
can
protect the other monkeys.3.He is selected out of one hundred and trained to be
a
monkey king.Key ExplanationЈєMonkeys are social animals who have a leader called
the monkey king. Only the monkey king can raise its tail. This is the signal of
a
leader. No one can imitate it. The monkey king must have the capability to solve
problemsЈ¬ beat back enemies bravely and protect the safety of others. A monkey
with the above abilities will be supported by others to be the monkey
king.Correct Answer: 2
Why doesnЎЇt the rabbit eat the grass around its den?1.It will eat the grass if
it
tastes delicious.2.The grass near the den usually tastes bad.3.The rabbit needs
a
place to hide itself.Key ExplanationЈєA rabbit excretes a substance on the grass
surrounding its den to indicate its sphere of influence. If it eats up the
grassЈ¬ it canЎЇt avoid attack from its enemy.Correct Answer: 3
Why are the ears of rabbits big and long?1.They can help fanning and radiating.
2.They can help locating enemies in time.3.They can push the grass aside and act
easily.Key explanationЈєThe rabbit has no ability to attack and harm other
animals. It can only jump and run away. So it must often erect its ears to
notice
movement all around.Correct Answer: 2
Why are the eyes of a white rabbit red?1.ItЎЇs the color reflected by blood in
its
eyeballs.2.Because it likes eating red radish, which is full of red
pigment.3.Because it has a disease, which makes its eyes red.Key ExplanationЈє
Rabbits have different color eyes because of different pigments in their bodies.
The white rabbit has no pigment in its body. The red color is in fact a
reflection of the blood in its eyeballs.Correct Answer: 1
How does the rabbit avoid its enemy?1.It can jump far and quickly.2.It can send
out a smell to repel the enemy.3.It has a useful protective color.Key
ExplanationЈєThe rabbit usually lives on the open plain. When in dangerЈ¬ it
will
run away from the dangerous area with its excellent jumping ability.Correct
Answer: 1
Why does rabbit make several dens at once?1.It builds only one den with several
entries.2.It builds several dens.3.It builds three dens.Key ExplanationЈєIn
factЈ¬
the rabbit does not make many the dens to avoid attack of its enemy. UsuallyЈ¬
there are many entries for it to flee in case of emergency.Correct Answer: 1
How does a frog prey on mosquitoes?1.It can change its body color to lure
mosquitoes closer.2.It can secrete mucus to seduce mosquitoes.3.ItЎЇs good at
jumping and using the mucus on its tongue to catch mosquitoes.Key ExplanationЈє
There are two methods that the frog commonly uses to catch injurious insectsЈє
Jumping capture and tongue-rolling capture. In the latter methodЈ¬ the mucus on
its tongue is used to catch mosquitoes.Correct Answer: 3
Where do frogs mate and spawn?1.They mate on the bank and spawn in water.2.They
mate in the water and spawn on the bank.3.Frogs seem to mate and spawn in the
waterЈ¬ but in fact they carry out external fertilization.Key ExplanationFrogs
seem to mate and spawn in the waterЈ¬ but in fact they carry out external
fertilization. When matingЈ¬ the male frog rides on the back of the female oneЈ¬
embracing its body tightly. After being stimulatedЈ¬ they will emit ovum and
semenЈ¬ then fertilization will be finished in water.Correct Answer: 3
Why doesnЎЇt the tail of the tadpole disappear after it grows up?1.The tail
can't
easily be found because it has grown smaller.2.It degenerate because it is
useless.3.It changes into the hind legs of the frog.Key ExplanationЈєThe little
tadpole needs to twist its tail to help swimming. During its growth periodЈ¬ its
four feet grow up while its tail gradually degeneratesЈ¬ eventually
disappearing.Correct Answer: 2
Why are the frogЎЇs cheeks constantly rising and shrinking?1.It's the way the
frog
breathes.2.For crying loudly.3.It's a means of saying hello.Key ExplanationЈє
Rising and shrinking its cheeks is the frogЎЇs unique way of breathing. The air
in
its mouth can be beaten into the lungЈ¬ like a pumpЈ¬ while breathing.Correct
Answer: 1
How do you tell apart a frog and a toad?1.1.Frogs often live in ponds while
toads
live in swamps.2.2.Frogs often move about after rainfall while toads are
active
at nigh in the summer.3.The skin of a frog is smooth and looks green or dark-
greenЈ¬ while that of the toad appears dark.Key ExplanationЈєThe most obvious
difference is that the skin of the frog is smooth and looks green or dark-green
while that of the toad appears darker.Correct Answer: 3
How is a frog able to live both in water and on land?1.Because it has a special
breathing organ.2.It can live on land temporarilyЈ¬ but most of the time it
should live in the water.3.It can swim in the water with the ability of holding
its breath for a long time.Key ExplanationЈєBecause the frog has a special
breathing organЈ¬ it is able to live both on land and in the water. When a young
tadpoleЈ¬ the frog breathes in the water using gills and can move quickly using
a
tale. When it maturesЈ¬ the frogЎЇs gills disappear and it breathes using lungs.
The frogЎЇs legs become strongerЈ¬ enabling it to move on land. But the frog
still
keeps its webbed toesЈ¬ which allow it to swim in the water.Correct Answer: 1
How can a snake crawl so quickly without legs?1.The skin can secrete mucus to
increase the speed of crawling.2.The outside scales can erect when crawling in
the shape of an Ў®SЎЇ 3.Crawling in the shape of the letter Ў®SЎЇ can enhance
power
and traction.Key ExplanationЈєWhen crawling in the shape of the letter Ў®SЎЇЈ¬
the
outside scales will raise a littleЈ¬ the tip of which can improve the snakeЎЇs
moving speed.Correct Answer: 2
How can a snake swallow objects bigger than its body?1.It has flexible ligaments
in its mouth.2.It can excrete acid in the mouth to digest the food
immediately.3.There is a square bone in the snakeЎЇs mouth which lets it open
its
mouth widely.Key ExplanationЈєBecause of a square bone in its mouthЈ¬ a snake
can
swallow food much bigger than its body. The bone can open its mouth widelyЈ¬ and
the gullet and stomach can expand with the size of the food.Correct Answer: 3
How does the tail of a rattlesnake make sound?1.The "Horn-wheel" at the end of
the rattlesnakeЎЇs tail can make sound as a small bell.2.The sound is caused by
the air entering into the "Horn-wheel" at the end of the rattlesnakeЎЇs
tail.3.As
the rattlesnake crawls it sways and beats the ground with its tailЈ¬ producing
the sound.Key ExplanationЈєAt the end of the rattlesnakeЎЇs tail there are
several "Horn-wheels"Ј¬ which are hollow inside. They can make sounds due to the
entry of air as soon as the snake waves its tail. In additionЈ¬ one extra "Horn-
wheel" will be added after the snake sheds its skin.Correct Answer: 2
How do you tell apart a viper and the common snake?1. 1.The viper has poisonous
teeth and its head usually is in the shape of a triangle.2.The viper has an
organ
to make sound.3.The skin color of the common snake is more glaring.Key
ExplanationЈєThe basic dissimilarity is whether it has poisonous teeth or not.
FortunatelyЈ¬ we can also judge according to the snakeЎЇs appearanceЈ¬ since it
is
not easy to see its teeth. Generally speakingЈ¬ the head of viper is bigger and
triangularЈ¬ and the streaks are more glaring. You 'd better get away
quickly.Correct Answer: 1
Is a bat a kind of bird?1 1.NoЈ¬ its predecessor is a mouse.2.YesЈ¬ because it
has
wings.3.ItЎЇs a kind of mammal instead of a bird.Key ExplanationЈєThe bat is a
kind of small animalЈ¬ belonging to the mammal family. It has four limbsЈ¬ but
the
front ones have degenerated. It is a viviparous animal with soft hair on its
bodyЈ¬ which is the same as other mammals.Correct Answer: 3
Why do bats hang upside down?1 1.They can fly away at once when in danger.2.They
are not comfortable standing.3.Sleeping upside down can help increase blood
circulation and recovery of physical power.Key ExplanationЈєThe bat is the only
mammal that can really fly. It has wide firm wingsЈ¬ but it can only crawl
slowly
with its hind legs. Hanging upside down in a high placeЈ¬ it can fly away at any
time if in danger.Correct Answer: 1
How does the bat see clearly in darkness?1.It can distinguish directions by
using
its eyesight.2.It can send out sound waves of high frequency with a special
structure known as a "nose-leaf". 3.It distinguishes directions with its earsЈ¬
as does a cat.Key ExplanationЈєWhen flyingЈ¬ the bat can send out sound waves of
high frequency with a special structure called a "nose-leaf"Ј¬ located on its
head when flying. The sound waveЈ¬ which people can't hearЈ¬ is reverberated if
something is ahead of it. So the bat can avoid obstacles easily in spite of
darkness.Correct Answer: 2
Are there any special characteristics in the mating behavior of foxes?1.The male
fox will smear a secretion on the hair of the female one to compel it to
submit.2.Before matingЈ¬ the male fox will do some actions near the female ones
to please them.3.The male fox will force the female one to submit.Key
ExplanationЈєBefore matingЈ¬ foxes will stand up on their hind legs to play a
kind
of Ў°gameЎ±. The male fox will smear a secretion on the body of the femaleЈ¬ the
smell of which will make the female excited.Correct Answer: 1
Why does the fox perform strange Ў°attraction behaviorЎ±?1.In order to get the
attention of the opposite sex.2.In order to gain compassion.3.To fool its
prey.Key ExplanationЈєSometimes the fox pretends to be crazyЈ¬ doing some
strange
actions like wallowing and turning somersaults. Birds and rabbits can't help but
come to see. The fox suddenly stops its performance and preys on them.Correct
Answer: 3
What is the function of the dog-ear foxЎЇs large ears?1.They can aid in hearing
and radiating heat.2.They have no special use3.They can help in fanning and
radiating heat.Key ExplanationЈєIn the hot desertЈ¬ the dog-ear foxЎЇs big ears
can
help to radiate heat in order to avoid an increase in temperature. They can also
distinguish sounds clearlyЈ¬ helping the dog-ear fox to protect itself.Correct
Answer: 1
What kind of animal likes eating antsЈї1.The fox. 2.The monkey.3.The
anteater.Key
ExplanationЈєAnteatersЈ¬ pangolinsЈ¬ boars and orangutans all like eating antsЈ¬
especially the anteater and pangolin. Ants are their main food. They use their
long tongues and mucus to eat ants.Correct Answer: 3
Why must the mouse constantly spoil objects by chewing on them?1.The mouse wants
to confirm whether the object is edible or not.2.The mouse wants to slow the
growth of itЎЇs front teeth.3.It is a mouseЎЇs nature.Key explanationЈєThere is
a
kind of marrow that is constantly secreted to help the growth of the mouseЎЇs
front teeth. It must often chafe on hard things to reduce the growth of its
front
teeth.Correct Answer: 2
Can the mole fly?1.It can only glide.2.Its furЈ¬ like a wingЈ¬ can help it to
fly.3.It's good at jumping though it can't fly.Key ExplanationЈєThe mole is an
animal with fur. It can balance its body when gliding down from a high place in
a
mountain forest with its flat tail. SoЈ¬ it is skillful at gliding instead of
flying.Correct Answer: 1
How does the south American baby-carrying mouse carry its baby?1.It carries its
baby in its mouth.2.The little one lies on its mother's chest or back.3.It holds
its baby with its front legs.Key ExplanationЈєAlthough the south American baby-
carrying mouse is a marsupial animalЈ¬ it has no baby-pouch. UsuallyЈ¬ the baby
can lie on its mother's chest. After growing upЈ¬ it will ride on the back of
its
motherЈ¬ who can climb quickly in spite of the weight of the baby.Correct
Answer:
2
What does the hedgehog do when it is in danger?1.It runs away.2.It erects its
spine to protect itself.3.It attacks its enemy with its sharp teeth.Key
ExplanationЈєIn order to protect itself when in dangerЈ¬ the hedgehog will
conceal
its headЈ¬ handsЈ¬ legsЈ¬ and other soft parts of its body. It shrinks its body
into a round formЈ¬ like a chestnutЈ¬ and erects its spine to avoid being
attacked.Correct Answer: 2
How can a gecko move on a sheer glass surface without falling? 1.Because it has
many deep furrows on its feet.2.Because there are suction cups on its
feet.3.Because its feet can excrete a kind of mucus.Key ExplanationЈєThe plaits
between the gecko's toes form many deep furrows. Because of the friction between
those deep furrows and the smooth surfaceЈ¬ and because of the geckoЎЇs special
absorption abilityЈ¬ the gecko can move on the surface of glass freely.Correct
Answer: 1
Why are geckos and lizards able to cut off their own tails?1. In order to flee
for their life.2. So their tails donЎЇt influence their ability to move.3.
They shed their tail and grow a new one with the change of seasons.4.
Key Explanation:The broken tails have the ability to regrow. So in an
emergency, geckos and lizards will cut off their tails without hesitation to
save
their lives.Correct Answer: 1.
English
Why do birds always sing songs? 1.To express their emotion.2.It is a kind of
instinct without any meaning.3.To be appreciated by people.Key
ExplanationЈєBirds
express their thoughts and feelings by singingЈ¬ this includes looking for
partners and foodЈ¬ protectingЈ¬ alertingЈ¬ etc. This is the result of long-term
adaptation to circumstance no matter whether the sound is short or complicatedЈ¬
sweet or offensive. It has great significance to the life of the bird.Correct
Answer: 1
Why canЎЇt a bird fall out of a tree?1.Fleshy patches on its claws can grasp the
tree branch tightly..2.Suction-cup like areas on the birdЎЇs claws can grip the
tree branch.3.ItЎЇs specially structured toes can hold the branch tightly.Key
ExplanationЈєThe first toe and three other toes of a bird are comparably longer
and adapted to hold a branch tightly. AdditionallyЈ¬ the toesЈ¬ under the strong
force of the birdЎЇs body weight and with specially structured bones and
ligamentsЈ¬ are able to hold the branch tightly.Correct Answer: 3
Why should little stones and sand be added to the forage of a bird?1.Little
stones and sand can substitute the function of teeth to grind food.2.They can
increase the birdЎЇs resistance to disease.3.They can open up the intestine to
avoid indigestion.Key ExplanationЈєThe majority of birds that eat stones and
sand
are vegetarian. Because they have no teethЈ¬ the food will reach their stomach
directly. The sand and little stones can help to grind up the food and promote
digestion. SoЈ¬ the sand and little stones have the function of teeth.Correct
Answer: 1
Why do different kinds of birds have different kinds of mouths?1.Because of a
difference in food selection.2.Because of a difference in living conditions.3.In
order to produce different sounds.Key ExplanationЈєThe shape of a birdЎЇs mouth
will depend upon the kind of food that it eats. For instanceЈ¬ the mouth of
swallow can open widely to tear up meat easily. The mouth-bag of a pond goose
can
pack a lot of little fish. The long and thin mouth of the humming bird is
convenient to suck honey.Correct Answer: 1
Why arenЎЇt migratory birds tired after flying long distance?1.It has
accumulated
energy by eating a great amount of food before flying.2.Because of its slight
body weight and vigorous metabolism.3.Because of its excellent wings and
outstanding endurance.Key ExplanationЈєMigratory birds depend upon their slight
body weight and metabolism to enable them to fly long distance. The energy it
needs comes from the oxygenation of organic substance. ThereforeЈ¬ after molting
in summerЈ¬ it begins to look for food and store fat to prepare for migration in
autumn and winter.Correct Answer: 2
How can a woodpecker stand vertically on the side of a tree?1.It is good at
chiseling holes.2.It has exceptional balance.3.It has very sharp hooks on its
claws..Key ExplanationЈєThe legs of a woodpecker are short and strong.
ParticularlyЈ¬ two of its toes are forward and the other two are backward. It
can
hold a tree tightly with the sharp hooks on the top of its toes. In additionЈ¬
the two feet holding the branch and the stiff feather on the tail divided into
two bundles become three separate pivots. So it can work vertically on the side
of a tree in balance.Correct Answer: 3
Is there any relationship between the swallow and an edible bird nest?1.The
edible bird nest is the excretion of the swallow in producing eggs.2.In fact it
is the tears of the swallow.3.It is the saliva of the swallow.Key ExplanationЈє
The edible bird nest is the nest of the golden-silk swallow. The material in the
nestЈ¬ which is its salivaЈ¬ is different from the clay used by the common
swallow. It contains colloidЈ¬ lower hydrophyte algaeЈ¬ and small fishЈ¬ which
all
cause it to solidify.Correct Answer: 3
How is a parrot able to speak?1. It can be trained to speak because of its
outstanding memory.2. It can speak after training because of its ability to
organize simple language.3. It can imitate people speaking because of its
tapered and fleshy tongue.4. Key ExplanationЈєThe parrot can speak simple
language by using its tapered and fleshy tongue to repeat a string of syllables
taught by people. The speaking is a kind of imitation instead of a conscious use
of language.Correct Answer: 3
Why does a peacock spread open its tail?1.Male peacocks show off to seek a
partner. 2.Female peacocks want to attract male ones.3.To threaten enemies.Key
ExplanationЈєDuring mating seasonЈ¬ male peacocks compete to show off their
attractiveness. So in the mating seasonЈ¬ at the end of spring and beginning of
summerЈ¬ peacocks in the zoo will open their tails if tourists with beautiful
clothes approach them.Correct Answer: 1
Why do hens cluck after producing eggs?1.As a means of relaxing. 2.To inform
cocks.3.Because of pain.Key ExplanationЈєProducing an egg usually takes ten to
twenty minutesЈ¬ sometimes even four to five hours. So after completionЈ¬ the
hen
will take a long time to rest. Then it clucks to show its pride and motherhood.
At the same timeЈ¬ it is informing the cock.Correct Answer: 2
Why does the hen always peck its egg?1.To help the chick break out from the
eggshell easily.2.It is quite upset on producing such a "bad egg" with too thin
of an eggshell.3.To protest that the cock doesn't give it moderate consideration
and protection.Key ExplanationЈєThe Egg is abundant in calcium. If the henЎЇs
diet
is lacking in bone powder or bony little fish full of calciumЈ¬ the hen will
produce an egg with a thin and soft eggshell. The hen will become irritated and
peck the "bad egg".Correct Answer: 2
Why are the two ends of an egg different sizes?1. The egg is compressed to
be thinner during the period of hatching.2. .It is the result of long-term
evolution because the egg must bump the ground after being produced.3. It
matches the shape of the chicken inside the egg.Key ExplanationЈєThe shape of an
egg matches the shape of the chicken inside. A chicken breaks the eggshell with
its mouth. Except for the force of the head and neckЈ¬ the feet need a pivot
point. The small part of the egg is the pivot. If the egg is too round or longЈ¬
it is difficult to find a pivot. So the egg won't be broken easily.Correct
Answer: 3
Why canЎЇt an ostrich fly?1.The wings of the ostrich have degenerated gradually
after long-term adaptation to life in the desert and grasslands.2.It has no
wingsЈ¬ although it is a bird.3.To provide a more comfortable lifeЈ¬ its wings
have degenerated.Key ExplanationЈєOstriches live in the desert and grasslands of
the southern hemisphere. Besides eating plantsЈ¬ they prey on small land
animals.
Their wings have degenerated after long-term adaptation to their environment.
But
their legs are very strong with two toes forward and thick skin under the feet.
They are not afraid of heat or of sinking into the sand. So ostriches can run
fast instead of flying.Correct Answer: 1
Does a duck feel cold in the water during winter?1.It can change its body
temperature with that of the water.2.The duck gets used to the water
temperatureЈ¬ which isnЎЇt really that cold.3.The duck has a thick layer of fat
and waterproof feathers.Key ExplanationЈє The thick fat and waterproof feathers
of the duck can keep it warm even in low temperatures. At the same timeЈ¬ it
won't be worried about water entering into its body.Correct Answer: 3
Why donЎЇt aquatic birds sink in water?1. 1.Because of their light body
weight.2. 2.Because their feathers are thick and 3. plump with fat
on their surface.4. 3. Buoyancy comes into being by paddling5. water
with webbed toes.Key ExplanationЈєAquatic birds always secrete fat from the back
of their tail root and smear it on their feathers Using their head and mouth .
Air can be stored among the thick and plump feathers to avoid sinking.Correct
Answer: 2
Why do seagulls like to fly along side oceangoing vessels?1.It can be absorbed
in
flying instead of alerting other animals.2.It can take advantage of the airflow
formed by the passage of oceangoing vessels to save energy in flight.3.It can
learn directions.Key ExplanationЈєWind is shaped from the flow of air. When it
comes across obstaclesЈ¬ like an oceangoing vesselЈ¬ the atmosphere will ascend
to
form a strong airflow. The seagull cleverly takes advantage of the strong
airflow to support its body. Thus it can fly lightly in the sky by following
oceangoing vessels.Correct Answer: 2
Why do owls regurgitate what they have already eaten?1.Because they always eat
too much.2.Because the food tastes bad.3.Because their stomach canЎЇt digest the
food.Key ExplanationЈєCarnivorous animals like the owl eat up all of their prey.
After eight to twenty-four hoursЈ¬ the owl will shake its head up and down and
vomit a round object. If you examine it carefullyЈ¬ you'll find bird feathers or
animal hair mixed inside. The owl expels those things that can not be
digested.Correct Answer: 3
English
How do jellyfish attack their enemy?1.With needle shaped objects at the end of
their tentaclesЈ¬ which can excrete anesthetic.2.With arista cells on their
tentacles which excrete poisonous liquid.3.Their tentacles will become as stiff
as needles upon coming across the enemy.Key ExplanationЈєThere are a lot of
arista cells with a prick bursa inside on the tentacles of the jellyfish.
Outside
the prick bursa are prods. When penetrating into the enemyЈ¬ these pricks will
fan out into the body. At the same timeЈ¬ they will excrete poisonous liquid to
anesthetize or kill the enemy.Correct Answer: 2
Why does the holothurian need to hibernate during the summer?1.There is little
food on the seafloor in the summerЈ¬ so the holothurian has to sleep to resist
hunger.2.It has to sleep to avoid attack from outside because there are a lot of
competitors in the summer.3.It has to sleep because it can not bear the high
temperature.Key ExplanationЈєMost living creatures in the sea move up and down
in
the water with the change of temperature. In the summerЈ¬ the surface
temperature
becomes high in strong sunshineЈ¬ and little living creatures on the seafloor
float to the surface of the sea to reproduce. The holothurian has to sleep to
make it through the hungry summer.Correct Answer: 1
Is coral a plant or an animal?1.It is an oreЈ¬ and can be made into
decorations.2.It is a plant shaped like a branch.3.It is a kind of lower
animalЈ¬
belonging to the species coelenterate.Key ExplanationЈєCoral belongs to the
species coelenterate which has inner and outer embryo layers only. It only has
an
opening for eating and excreting. It preys on food with tentacles around the
opening. UsuallyЈ¬ coral is made of a lot of "coral-bugs" connecting each other
into a group shaped like a branch. Coral we see is in fact usually a group of
coral-bugs together.Correct Answer: 3
How does the clam eat things without a mouth?1.It opens its shell for
eating.2.It
uses little pores to take plankton in as food.3.It keeps its life by
accidentally
opening its shell to swallow large amounts of food.Key ExplanationЈєThere are
two
pores running parallel to each other at the end of the shell. They connect with
tiny pipes to keep intimate contact with the outside world even though the shell
can be closed for a long time. The circulation of water brings plankton and
oxygen in to avoid hunger and suffocation.Correct Answer: 2
How does a clam walk?1.It depends upon the flexibility of muscles in its Ў°axe-
footЎ±.2.It moves with the help of seawater and other animals.3.It moves slowly
with tiny meat-feet on both sides of its shell.Key ExplanationЈєThere is a white
meat like axe called the "axe-foot " in the shell with strips of muscles on it.
The clam can walk slowly by flexible movement of these muscles.Correct Answer: 1
15-3.Why does the shell of a clam open naturally after boiling?1.Because colloid
for connection becomes stiff after boiling.2.It loses the ability to close the
shell after boiling.3.The muscle used to close the shell becomes too hard to
expand and contract.Key ExplanationЈєClams open and close their shells with the
closing-shell muscle and ligamentЈ¬ which are in the shape of a cylinder and
commonly called the "dried scallop". The shell can close by contracting the
closing-shell muscle. This flexible ligament will expand and cause the shell to
open after boiling.Correct Answer: 3
Why are there pearls in a shell? 1.Because a special substance
inside the shell will become a pearl after its death.2.It can excrete pearl
substance to surround material taken from outside to produce a pearl. 3.In
factЈ¬
pearls are quite rare among shellfish.Key ExplanationЈєFor self-protectionЈ¬ a
shellfish will excrete pearl substance to surround parasites and foreign matter
which enter into its body. ThenЈ¬ a pearl comes into being after a long
time.Correct Answer: 2
Can clams live in stones?1.NoЈ¬ they can only stay there temporarily to avoid
their enemies.2.Some clams can. They §гan excrete a kind of acid to erode stones
into grottos to live in.3.All clams can.Key ExplanationЈєSome clams can live in
stonesЈ¬ because they can secrete a kind of acid from their feet to corrode and
loosen the stones. Then using their feet and water pipes as a pivotЈ¬ they spin
their shells to rub the stones into grottos.Correct Answer: 2
Why doesnЎЇt a hermit crab live in its own shell?1. It has to change a shell
because its own can't grow up.2.It has to hide itself in the spiral shell for
protection because it has no stiff shell and can't move quickly.3.It lives
together with the spiral shell because they are good friends.Key
ExplanationЈєThe
Hermit crab can't swim like a shrimp and it has no hard shell like a crab. So
the
spiral shell becomes a natural refuge for it. With the growth of its bodyЈ¬ it
will find another more suitable spiral shell to live in. It will even eat the
meat of the spiral shell if it can not find a suitable one for a period of
time.Correct Answer: 2
Why will a crab spit foam after leaving the water?1.It can store water in its
gills. After it breathes air on shoreЈ¬ the water will change into white
foam.2.It produces foam-like water to help it breathe after leaving
water.3.Because of difficulty in breathing.Key ExplanationЈєThe crab will not
die
from dryness because it can store water in its gills. It breathes large amounts
of air on shoreЈ¬ which will be taken in from the two sides of its mouth. The
water in its gills will be spit out at the same time.Correct Answer: 1
Why can a crab only crawl sideways?1.This is safer because its eyes can not look
forward.2.It will tangle itself up if it moves straight ahead.3.Its feet only
can
move up and down because there is no turning joint on its feet.Key ExplanationЈє
Except for a pair of pincers for protection and preying on foodЈ¬ the crabЎЇs
other four pairs of feet are for moving. Each is comprised of seven parts. But
there are no turning joints between two parts. Walking-feet can only move up and
down by moving strips of muscle connecting to outer bone.Correct Answer: 3
Why are the feet of a crab so little?1.Because the feet can grow out only after
the crab molts.2.Some of the feet are particularly small because of its
different
speed of growth.3.Some feet have degenerated gradually because they are seldom
used.Key ExplanationЈєWe can catch a crab by holding its head and the two sides
of its chest with the thumb and middle finger. If we only hold a pincer or
walking-footЈ¬ the crab will clip you or run away by giving up the foot which is
seized. The broken foot can be reproduced. The new one is usually smaller
because
the crab has probably molted several times already.Correct Answer: 1
Where does the hair-crab like to live in winter?1.It will go back to the sea in
winter because rivers will freeze.2.It will return to the sea at the beginning
of
winter in order to spawn.3.It will return to the sea because rivers suffer from
a
food shortage during the winter.Key ExplanationЈєThe hair crab is a migratory
animal living in water. It is an "amphibious crab" liking both seawater and
fresh
water. It usually mates at the juncture of the river and sea; then it produces
eggs in the sea. The eggs will not be hatched until spring comes. The crab will
stay in the sea until its death after production.Correct Answer: 2
Why do shrimp and crabs turn red after boiling? 1.There is only red pigment left
in their body after boiling.2.Their colorless blood turns red after boiling.3.A
layer of protective colloid becomes red after boiling.Key ExplanationЈєThe color
of shrimp and crabs is mainly due to their pigment cells located in derma under
their shells. Although shrimp have many kinds of pigment cellsЈ¬ red ones are
predominant. After boilingЈ¬ only the red pigment remain. So the body turns
red.Correct Answer: 1
Why does the green turtle break into tears while producing eggs?1.In order to
make the eyes moist to prevent sand entering them.2.To rinse sand out from the
eyes.3.Because of the pain of producing eggs.Key ExplanationЈєThe clever green
turtle knows clearly that it will feel uncomfortable if sand enters into its
eyes. So it breaks into tears first to protect its eyes.Correct Answer: 1
Why is there dark ink in the stomach of a cuttlefish?1.It is used to baffle the
enemy for self-protection.2.Dark juice is an excretion.3.It is an acid used to
digest food.Key ExplanationЈєThere is a black bag in the stomach of the
cuttlefish which stores black juiceЈ¬ which is a kind of protective device for
use in an emergency. The cuttlefish will spray some black ink to contaminate the
surrounding water when coming across an enemy. It can run away easily while the
enemy is confused.Correct Answer: 1
How does a cuttlefish walk?1.By paddling water with its several
tentacles.2.Through the power of "spurting water".3.By paddling water with two
meat-slices which are like fins at the end of its tail.Key ExplanationЈєThe
cuttlefish goes forward through the power of "spurting water"Ј¬ which is
different from other fish. It is very quick because of the great power coming
from "spurting water". It has to absorb water to supplement its energy once the
water in its body has been used up.Correct Answer: 2
Is there blood in the body of a cuttlefish?1.NoЈ¬ it is a kind of animal without
vertebra.2.There isЈ¬ but the blood can not be found easily because it is mixed
in with black succus.3.There isЈ¬ but the blood is colorless because it lacks
red
pigment.Key ExplanationЈєThe cuttlefish has a complete blood vessel structure
with blood in it. The blood in common animals appears red due to its red
pigment.
The blood of cuttlefish is colorless because it has colorless "serum" instead of
red pigment.Correct Answer: 3
Why does an octopus sometimes hide in a grotto?1.The narrow entry of its den in
a
grotto can help in defense.2.It can avoid an attack during mating.3.It has to
hide in the grotto because it can't resist its enemy.Key ExplanationЈєThe
octopus
likes living in grottos or rock crevicesЈ¬ which can supply a good resting place
for it to sleep in daytimeЈ¬ because enemies can't enter through the narrow
entryway. If it can't find a ready-made grottoЈ¬ it will dig a hole at the
bottom
of the sea with shells around.Correct Answer: 1
How does an octopus prey on its victims?1.It uses its countless suckers to
absorb
the victim.2.It can catch the victim by moving its feetЈ¬ which are very
agile.3.It spurts out dark ink to anesthetize its victim.Key ExplanationЈєThe
octopus can change its body color depending upon circumstances. It can disguise
itself to cheat the enemy and victim. It will appear suddenly to grasp the
victim
tightly when it finds it. The countless suckers on its feet can hold the victim
strongly.Correct Answer: 1
Do fish need to sleep?1.They like sleeping amongst aquatic plants and
rocks.2.YesЈ¬ but it is difficult to distinguish whether they are sleeping or
not
because they have no eyelids.3.They don't need to sleep.Key ExplanationЈєIt is
difficult to distinguish whether fish are sleeping or not because they have no
eyelids. Generally speakingЈ¬ they stop moving when sleepingЈ¬ but still wave
their gill coverЈ¬ dorsal fin and tail to keep balance. AdditionallyЈ¬ their
sleeping time is shortЈ¬ and they are very alert when sleeping.Correct Answer: 2
What purpose does mucus on the scales of a fish serve?1.To prevent salt from
entering into the fishЎЇs bodyЈ¬ resulting in death.2.It has the function of
protecting the fish and reducing friction in the water to make the fish swim
easier.3.Mucus can prevent the loss of body temperatureЈ¬ since the fish is a
temperature-changing animal.Key ExplanationЈєThe mucus all over a fishЎЇs scales
can reduce its friction in waterЈ¬ which makes the fish swim more effortlessly.
At the same timeЈ¬ it protects the fish from attacks by parasitesЈ¬ and bacteria
as well as other microorganisms. It also helps by not allowing harmful
substances
through the permeable skin of the fish.Correct Answer: 2
How can we judge the age of a fish from its scales?1.Count the number of
scales.2.Observe the size of the scales.3.Count the number of thinner pieces of
fish scales.Key ExplanationЈєMost fish already have scales when they are one
year
oldЈ¬ according to the regular growing pattern of fish. Every scale is composed
of many thinner pieces of different sizes. Older fish have thinner pieces
characterized as suchЈє middle layers thickЈ¬ outer one thinЈ¬ top one small.
Younger fish have thinner piecesЈ¬ the lowest layer being the biggest. Thinner
pieces will grow in number with the growth of the fish.Correct Answer: 3
Does every kind of fish have the same number of bones?1.The number of bones
varies with the size of the fishЎЇs body.2.Sea fish have more bones than fresh
water ones.3.The more evolved a fish isЈ¬ the fewer the number of bones that it
will have.Key ExplanationЈєThe number of bones an animal will have will get
fewer
along with the extent that it has evolved. For instanceЈ¬ the bonito has 159
head
bones compared to man's 23. So more evolved fish have fewer bones. Take for
example the yellow fish. Less evolved fish have more bonesЈ¬such as the
bonito.Correct Answer: 3
Can we determine the sex of a fish from its shape?1.Yes. Male fish have a
brighter body color during mating season.2.Yes. The position of the stomach is
differentЈє maleЎЄleft sideЈ¬ femaleЎЄright side.3.No. They are the same.Key
ExplanationЈєThere are over 20Ј¬000 kinds of fish. Although in some species the
sex can be discerned easily by the fishЎЇs shapeЈ¬ the majority of them have no
sex-distinguishing features. But during the mating season male fish will become
brighter in color.Correct Answer: 1
Why do fish gather around an ice-hole?1.For warmth.2.For breathing.3.For
companionship.Key ExplanationЈєThe reason that fish gather around an ice-hole is
that the water nearby can dissolve oxygen from the air for the fish to breathe.
When a lake is freezingЈ¬ the bottom water will be short of oxygen firstЈ¬ the
upper water later becoming so. Fish will find it hard to live in the bottom
waterЈ¬ so they move up and gather around ice-holesЈ¬ which have more contact
with
air.Correct Answer: 2
How do fish sink and float in water?1. Their bodies are full of water.2.Fish
have
streamlined body shapes and special flotation pockets in their bodies.3.They
float and sink depending on the non-stop waving of their gills.Key ExplanationЈє
Fish can sink and float in water because of their streamlined body shape and the
flotation pockets located in their bodies. The air in these pockets comes not
only by breathing with a short pipe while the fishЎЇs head floats above the
waterЎЇs surfaceЈ¬ but also by gills absorbing the air dissolved in plentiful
red
blood cells.Correct Answer: 2
Why will fish die without water?1.Fish can't breathe with gills without
water.2.Fish will die because of dissipation of water in their bodies.3.Without
the supporting buoyancy of waterЈ¬ they can not support their body weight.Key
ExplanationЈєFish can use gills to breathe the oxygen dissolved in water. Gills
can't separate the oxygen from air without water.Correct Answer: 1
Is it necessary for fish to drink even though they live in water?1.Fresh water
fish take in water through the outer skin of film on their gillsЈ¬ while
seawater
fish need to drink a lot of water.2.NoЈ¬ they can absorb water automatically
because their skin is permeable.3.YesЈ¬ they drink when thirsty.Key
ExplanationЈє
Fresh water fish needn't drink to replenish water because water can permeate
into
their body through the semipermeable outer skin of their gills because the
density of body fluid is higher than the water nearby. On the contraryЈ¬
seawater
fish must drink a lot of water to replenish water and dispose the unnecessary
salt because the density of salt in seawater is higher than that of the water
inside seawater fish. CommonlyЈ¬ seawater fish lose water in large
quantities.Correct Answer: 1
Why is the color of ornamental fish extremely bright?1.Because of a sudden
genetic change.2.Because of human-controlled breeding.3.The bright color of
ornamental fish is caused by color cells.Key ExplanationЈєThe color of
ornamental
fish is brightЈ¬ because the derma and scales of those fish have color cellsЈ¬
which make their body colorful. Some of them are extremely beautiful. They are
sent to aquariums or gardens as ornamental fish.Correct Answer: 3
Is there a lot of salt in the bodies of seawater fish?1.No, salt-sorting cells
can dispose unnecessary salt out of their bodies.2.Seawater doesn't have much
saltЈ¬ so there is not much salt left in their bodies.3.Fish have a special
digestive system to filter the salt out.Key ExplanationЈєSeawater fish will not
drink much water unless using gills to breathe. NormallyЈ¬ unnecessary salt will
be disposed of from the salt-sorting cells nearby the gill.Correct Answer: 1
Why do carp like to jump in water?1.They are naturally active and like
jumping.2.The are naturally aggressiveЈ¬ and jump to compete.3.They are
naturally
timid and jump because of fear.Key ExplanationЈєMany fish like jumping. Some
fishermen utilize this to catch fish. Fish jump to bypass obstacles and to catch
food quickly or to avoid sudden attack from an enemy. CarpЈ¬ which are naturally
activeЈ¬ enjoy jumpingЈ¬ especially at dusk. Sometimes their jumping is like a
game.Correct Answer: 1
Why do whales swim back to the Antarctic every year?1.Whales are not afraid of
the coldЈ¬ they like the Antarctic.2.Whales swim to the Antarctic to avoid
capture by humans and pollution.3.In the spring and summer of every yearЈ¬ there
will be a lot of shrimp and fishЈ¬ which whales like to eatЈ¬ in the
Antarctic.Key
ExplanationЈєThere will be a lot of plankton in the Antarctic in the spring of
every year. Plankton is the best food for black-eyed shrimpЈ¬ which is the best
food for the whale to eat. But in autumnЈ¬ it's not suitable for living
creatures
to grow at the low temperature. Whales swim back north due to the shortage of
food.Correct Answer: 3
Why will a whale die on land?1.Because of excessive loss of water.2.It is not
suitable to life on land.3.Its skeleton can't sustain its huge weight on landЈ¬
and its internal organs will be crushed.Key ExplanationЈєThe reason that a whale
can't live on land is not relevant to its lungs. There is no water-floating
force
to share the huge weight of its body on land. Internal organs are stressed too
muchЈ¬ which causes difficulty of breathing and blood-circulationЈ¬ and even
death.Correct Answer: 3
Why do globefish plump up their stomachs?1.To frighten the enemy.2.For
beauty.3.This is caused by the extremely huge flotation pocket in its body.Key
ExplanationЈєThere is a backward air pocket beneath the front of its intestines.
When it is under attackЈ¬ it will float quickly to the water surfaceЈ¬ open its
mouth and engulf air to fill the air pocket. This is a method to protect itself
from being swallowed or hurt by the enemy.Correct Answer: 1
How is the numbfish able to release electricity?1. It has stronger electricity
than other animals have.2.It lives in the sea with electricity.3.It can't
release
electricity. It releases a kind of venomous liquid that when touched produces an
electric shock.Key ExplanationЈєThe cause of electricity is the combination
ofions with positive charge together with an ions with negative charge. Animals
and plants have both ions that cause electricityЈ¬ the majority of which are
feebleЈ¬ while the numbfish's are strong.Correct Answer: 1
Does the male seahorse really give birth to the baby seahorse?1.The seahorse is
unisexual.2.The female seahorse sends the egg to the breeding-bag of the male
for
hatching.3.The female seahorse places the egg into the stomach of the male for
hatching.Key ExplanationЈєTo avoid being eaten by other sorts of fishЈ¬ the
female
seahorse sends the egg to the breeding-bag of the male. At this timeЈ¬ the
embryo
gets necessary nutrition by a thick web of blood vessels. The male seahorse
begins to give birth to its baby after it grows sufficiently in the breeding
bag.Correct Answer: 2
How does the penguin hatch its egg?1.The father penguin puts the egg on closed
feet and covers it with his stomach.2.It is hatched by the body temperature of
both mother and father penguin embracing it together.3.It is hatched in the
mother penguin's armpit.Key ExplanationЈєPenguins don't build a den after
producing an egg. The female penguin looks for food in the sea immediately. At
this timeЈ¬ the well-fed male closes its feetЈ¬ puts the egg on them with his
mouth and then covers the egg with its stomach. It will hatch the egg without
eating and drinking until the female comes back.Correct Answer: 1
English
Why does a tiger have streaks on its body?1.They have no purpose aside from
making the tiger look beautiful. 2. They are the best protective color for the
tiger.3.They distinguish the male from the female.Key ExplanationЈєThe tiger
usually lives in grassy or forested areas. In order to adapt its color to its
surroundingsЈ¬ its hair color and streak gradually become the "protective
color".Correct Answer: 2
How does a lion mark its territory?1.By marking it with fixed objects.2.By means
of urinating. 3.By distinguishing it with signals.Key ExplanationЈєUsuallyЈ¬ a
group of lions is composed of several mature male lionsЈ¬ and a majority of
female and little ones. The male lions will set their sphere of influence by
means of urinating in order to protect others in their group from outside
invasion.Correct Answer: 2
How successful is the lion when hunting?1.It is successful one out of seven
times.2.It is successful every other time.3.It is successful one out of five
times.Key ExplanationЈєThe lion is probably the best hunter in the animal world.
It is successful once in five times while hunting. SoЈ¬ after catching something
edibleЈ¬ it usually eats to satiation to prevent hunger in time of food
shortage.
It can eat nothing for about a week after fully eating.Correct Answer: 3
Is the elephant really afraid of the little mouse?1.It is not afraid of the
mouse
at all.2.It loathes the noise made by mouse.3.It is in fact afraid of small
animalsЈ¬not just the mouseЈ¬ entering its body.Key ExplanationЈєBecause of its
huge body and large body cavitiesЈ¬ the elephant will feel pain if small animals
enter into its body. Any incursion of foreign matter will cause it to
suffer.Correct Answer: 3
Why doesnЎЇt the elephant choke when it uses its trunk to drink water?1.Because
its trachea doesn't connect with its gullet.2.Its trachea connects with the
gulletЈ¬ but between them a cartilage valve can open or close at any time.3.Its
trachea connects with its gulletЈ¬ but its lungs can close temporarily. Key
ExplanationЈєThe trachea and gullet of the elephant are connected to each
otherЈ¬
but there is a cartilage valve on top of the gulletЈ¬ which will cover the
trachea when the elephant drinks water. Thus the water will not enter into its
trachea.Correct Answer: 2
What does an elephant do before it relieves itself?1.It lifts its leg like a
dog.2. It digs a hole.3.It raises its tail.Key ExplanationЈєThe elephant is very
fond of cleanlinessЈ¬ it doesn't want to make its tail and legs dirty while
relieving itself. Before emptying its bowels it will raise its tail. Before
urinating it will separate its hind legs.Correct Answer: 3
Why does the boar have long and sharp teeth?1.They are used as a weapon to
resist
the enemy.2.They are used to look for food.3.They help in chewing food.Key
ExplanationЈєWhen in an emergencyЈ¬ the boar will lower its headЈ¬wave it back
and
forthЈ¬ and rush straight forward. At that timeЈ¬ its long and sharp teeth
become
an effective weapon.Correct Answer: 1
Why do quills grow all over the body of the porcupine? 1. 1.The quills make
the porcupine look beautiful.2. 2.The quills help the porcupine to resist its
enemies. 3. 3.The quills can be used by the porcupine to prey on little
animals.Key Explanation: The quills on the body of the porcupine grow from its
mane. They are an effective weapon when defending against the attack of an
enemy,
it erects its quills with a "zip" to stand to threaten them.Correct Answer: 2
Can bears climb trees?1. They can't at all.2. Some can , others can
not.3. They are good at climbing trees , but seldom do because of their heavy
weight.Key ExplanationЈєBears are skillful at climbing treesЈ¬ but they seldom
do
because of their heavy weight. Only little ones like doing it. SoЈ¬ upon meeting
a bear it isnЎЇt necessarily safe to climb a treeCorrect Answer: 3
Why doesnЎЇt a polar bear slip when walking on ice?1.The acetabulum on its soles
can absorb the ice.2.The caruncle on its soles functions like a spike.3.Its
soles
are full of hairЈ¬ which can keep it warm and help prevent slipping.Key
ExplanationЈєThe polar bear has a dense clump of hair on its sole. It can run as
well on ice as on landЈ¬ without fear of slipping.Correct Answer: 3
Is a raccoon baby different from its parents? 1.The only difference is in
size.2.The only difference is in color.3.The raccoon baby has no black spots
around its eyes.Key ExplanationЈєThe biggest difference between a raccoon and
its
baby is that there are no black spots around the babyЎЇs eyes. In additionЈ¬ a
raccoon baby canЎЇt open its eyes until 26 days after birth.Correct Answer: 3
Why does the raccoon wash its hands before eating?1.It washes its hands because
it likes cleanliness.2.It washes its legsЈ¬ not its hands.3.It looks for food in
water instead of washing its hands.Key ExplanationЈєThe front legs of the racoon
are very sensitive. It knows whether food is edible or not as soon as it touches
it. Its main foods are fishЈ¬ shrimpЈ¬ and crab. SoЈ¬ it always looks for food
in
water.Correct Answer: 3
How can a koala sleep in a tree without fear of falling out?1.It can find stiff
branches and support its body with its hind limbs.2.It stands on a branchЈ¬
embracing it tightly.3.Something like suction cups on the soles of its feet can
grip the tree. Key ExplanationЈєThe koala bear eats only the leaves of the
eucalyptus tree. When sleepingЈ¬ it embraces the branch with its four limbsЈ¬
holding on especially tightly with the soles of its feet. Thus it will certainly
not fall down.Correct Answer: 2
How is the baby pouch of the koala bear different from the kangarooЎЇs?1.It will
not harm the baby when climbing trees.2.Its baby can enter in and out freely.3.
It can not be found by the enemy.Key ExplanationЈєThe koala bear not only eats
leavesЈ¬ but it also lives in tree holes. Its baby-pouchЈ¬ unlike that of the
kangarooЈ¬ faces down to protect the baby from being bumped when the koala bear
climbs up and down trees.Correct Answer: 1
Does the koala bear have a tail or not?1.Its name comes from the fact that it
has
no tail.2.The majority of koala bears have no tailЈ¬ only a few of them have a
tail.3.It has a tailЈ¬ but it is too small and short to be seen.Key
ExplanationЈє
In factЈ¬ koala bears have a tail. But the tail is too small and short to be
seen.Correct Answer: 3
Where does the horn of the rhinoceros come from?1.It is hair that hardens to
form
the horn.2.It is related to its genetics.3.Its nose changes into a horn.Key
ExplanationЈєThere are many kinds of rhinoceros. Only the Java rhinoceros has a
big-head horn. All the rest have two horns. In factЈ¬ the horn grows from hair
without marrow. It is the rhinocerosЎЇ weapon.Correct Answer: 1
Why do rhinoceroses and elephants smear mud on their bodies? 1.They don't like
cleanliness.2.To avoid evaporation of moisture and drive away insects.3.They are
taking a bath.Key ExplanationЈєMost rhinoceroses and elephants live in tropical
areasЈ¬ they like taking a bath in water frequently to cool themselves. They
smear mud onto their bodies to make a protective film after bathing and to avoid
the evaporation of moisture. At the same timeЈ¬ it can protect against the bites
of lice and insects.Correct Answer: 2
Why are hippopotamuses always bathing in water?1.Because they want to make sure
that their skin doesnЎЇt become too dry.2.Because they are afraid of the heat.
Bathing in the water is much cooler.3.It is easier for the hippopotamus to move
its large body while in the water.Key ExplanationЈєThe skin of the hippopotamus
is between two and three centimeters thick. It dries out very easily. In order
to
prevent this from happeningЈ¬ the hippopotamus must soak itself for long periods
of time. A layer of mucus protects the hippopotamusЎЇ skin.Correct Answer: 1
Why does the zebra have black and white stripes?1.They can confuse the eyesight
of the zebrasЎЇ enemy.2.The stripes can alarm other animals.3.It has no use but
it
is a genetic characteristic.Key ExplanationЈєThe streaks on the body of the
zebra
are a kind of protective adaptation. In the bright sunshineЈ¬ they can destroy
and decentralize the outline of the zebraЎЇs body. It is difficult to
distinguish
it clearlyЈ¬ which can help it to avoid attack.Correct Answer: 1
Why does the giraffe seldom drink water?1.It can store water like a camel.2.Its
main food is abundant in moisture.3.Because it has adapted to an arid
climate.Key
ExplanationЈєThe giraffe is able to live in arid places because it eats tender
leaves and sprouts filled with moisture.Correct Answer: 2
Why does the giraffe sleep standing up?1.ActuallyЈ¬ most giraffes lie down to
sleep.2.They sleep standing up in order to defend themselves from their
enemy.3.ItЎЇs hard work for them to lie down and then stand up.Key ExplanationЈє
The giraffe has no ability to struggle with its enemy. It can only run away as
soon as it sees the enemy. So it has to keep standing in order to get ready to
run away at any time.Correct Answer: 2
Why is the neck of the giraffe particularly long?1.It looks beautiful and is
attractive to the opposite sex.2.The giraffe needs a long neck in order to eat
the tender leaves and buds on trees.3.The giraffe needs a long neck in order to
match its long legs and keep balance.Key ExplanationЈєThe long neck of the
giraffe can be used to easily reach the tender leaves and buds on trees. This is
the result of the giraffeЎЇs adapting to its environmentCorrect Answer: 2
Does a panda have six fingers?1.The sixth finger is a fleshy pad.2.The sixth
finger is a protruding bone.3.The panda is a kind of animal with six fingers.Key
ExplanationЈєThe panda uses its five fingers and the protruded fleshy pad to
clip
the bamboo leaves and branches. As with humansЈ¬ its fingers will twist to the
inside when holding something.Correct Answer: 1
Does the panda belong to the cat family or the bear family?1.It belongs to the
panda family.2.It belongs to the bear family.3.It belongs to the cat family.Key
ExplanationЈєThe panda is a special rare carnivorous animal only living in
eastern Asia. Pandas only live in mountainous areas of Sichuan province and
Tibet. At presentЈ¬ zoologists classify pandas in the "panda family".Correct
Answer: 1
Why canЎЇt the panther run for long distances?1.ItЎЇs not necessary for it
because
it can pray on objects easily.2.Its paws protrude forwardЈ¬ so it can run fast
only for a short distance.3.It has weak physical power and endurance. Key
ExplanationЈєThe panther is the fastest animal. It can reach a speed of 110
kilometers per hour. Because of its protruded pawsЈ¬ it can only run for a short
distance despite its high speed.Correct Answer: 2
Where does the leopard hide its leftover food?1.It puts it into a tree2.It
throws
it away.3.It buries it temporarily.Key ExplanationЈєThe leopard is able to put
the dead body of the antelopeЈ¬ which weighs more than the leopardЈ¬ into a
tree.
Being hung in the tree in the shape of a "v"Ј¬ the antelope will not be eaten by
other animalsЈ¬ such as the mane.Correct Answer: 1
Why does the orangutan make a fist when walking?1.So it can attack its enemy at
any time.2.So it can carry something when walking.3.So it can walk quickly.Key
ExplanationЈєThe orangutan holds its fist close to the ground when walkingЈ¬
thus
it can carry objects at any time.Correct Answer: 2
Why is the tail of the kangaroo also its fifth foot?1.It can help to support the
weight of its body independently.2.It can help the hind feet to support its
body.3.It can help the front feet to support its body.Key ExplanationЈєThe
kangaroo is good at jumpingЈ¬ howeverЈ¬ its four feet can not alternate their
steps. When movingЈ¬ its hind feet and front ones step out
simultaneously.Correct
Answer: 2
Do the scales of the pangolin have any use?1.They help the pangolin to stay
warm.2.They prevent too much moisture from entering the pangolinЎЇs body.3.They
are the best protective color and material.Key ExplanationЈєThe pangolin looks
like a pinecone when it is curled up. The stiff and big scales outside the
pinecone are the best protective color and material. The scales look like
withered leaves when the pangolin is on the tree or in the brushwood.Correct
Answer: 3
How does the antelope inform its partner of its location?1.By urinating.2.By
crying.3.By an excretion from under its eyes.Key ExplanationЈєThere is a kind of
gland under the eyes of the antelopeЈ¬ which can excrete a substance with a
special smell. The antelope smears the excretion on trees to tell others its
location and situation.Correct Answer: 3
Which part of the body does the deer use to struggle with its enemy?1.The horns
on the head.2.It kicks its enemy with its strong hind legs.3.It cries loudly to
frighten its enemy.Key ExplanationЈєDeer seldom struggle with others. Only
during
the mating season will male deer fight over female deer. They use their horns as
weapons.Correct Answer: 1
How does a beaver alert other beavers in the event of danger?1.It communicates
with other beavers directly using sounds.2.It claps the water in an effort to
sound the alarm.3.As a social animalЈ¬ beavers alert one another to danger by
clapping each other.Key ExplanationЈєThe beaverЎЇs tail can help it to swim and
change direction. When in dangerЈ¬ its tail will clap the water forcefully Ј¬
making great noise to warn other beavers near by.Correct Answer: 2
Why do beavers build dams?1.They can easily check on the water level at the
mouth
of their den and build the dam.2.Building the dam can supplement the beaverЎЇs
water supply.3.In order to conceal the mouth of its den in waterЈ¬ it builds the
dam to keep the water level.Key ExplanationЈєBeavers usually make their dens in
rivers and marshes. They set the mouth of their den in the water in order to
avoid discovery by their enemy. So they must keep the water level
constant.Correct Answer: 3
Why donЎЇt beavers drown in water? 1.They do not stay a long time in the
water.2.Skin on the beaverЎЇs cheeks prevent water from entering its
mouth.3.They
can stop breathing for a long time.Key ExplanationЈєMost of the body structures
of the beaver are formed due to long-term life in the water. If holding twigs in
the mouthЈ¬ the skin on the cheek can prevent its mouth from taking in water.
When divingЈ¬ there are gristles both in the nose and eyes to avoid the entry of
water. Smear grease excreted around the beaverЎЇs anus can keep its hair dry. So
the beaver can not drown or freeze to death.Correct Answer: 2
How does the sea otter eat the meat inside a shell?1.It can easily bite though
the shell with its stiff teeth.2.It carries the shellfish onto the beachЈ¬ and
it
lets them open in the sunshine.3.It can break the ligaments of shellfish by
using
its sharp teeth.Key ExplanationЈєWhen eating shellfishЈ¬ the sea otter can break
the shell with its teeth or by beating two shellfish together. SometimesЈ¬ it
holds a stone on its chest to break the shell.Correct Answer: 1
How does the skunk protect itself?1.It climbs a tree when in danger.2.Other
animals don't want to approach it at all because of its stench.3.It can send out
a disgusting odor to frighten its enemy.Key ExplanationЈєThere is a kind of
gland
under the tail of the skunkЈ¬ which can excrete liquid. When in dangerЈ¬ it can
send out a repulsive smell in order to help it escape.Correct Answer: 3
Why is the duckbilled platypus considered to be a mammal even though it lays
eggs?
1.Because it lives most of its life in the waterЈ¬ it canЎЇt give birth to its
young like other mammals.2.Like a kangarooЈ¬ it fosters its baby in its
belly.3.The egg is a kind of film to protect the baby.Key ExplanationЈєThe water
living duckbilled platypus of Australia is the most unusual mammal. It produces
eggs, which hatch after a period of ten days. It will also go though a period of
lactation. So it is regarded as a mammal.Correct Answer: 1
English
Why does a dog pant on a hot day?1.ItЎЇs a habitual action.2.It means it is
thirsty.3.It can help in radiating heat.Key ExplanationЈєA dog can not perspire
because it lacks sweat glands and pores on its skin. But there are a lot of
sweat
glands and pores on its tongue. So on hot daysЈ¬ dogs begin panting immediately
in order to help in radiating heat.Correct Answer: 3
How does a dog express its emotion?1.By the action of its four limbs.2.By using
its tail to express its feelings.3.Showing it is afraid by instantly barking.Key
ExplanationЈєThe dog shows its feelings mainly by the action of its tail. When
it
is confident Ј¬ it will clip its tail to be docile; and when it gets ready to
attackЈ¬ its tail will flex into an certain angle.Correct Answer: 2
Why is the tip of a dogЎЇs nose always wet?1. Because dogs lack sweat glandsЈ¬
theydepend upon their noses to help radiate heat.2.It must secrete mucus to
moisten its olfactory cell.3.If a dogЎЇs nose becomes dryЈ¬ it means the dog is
thirsty.Key ExplanationЈєA dogЎЇs nose has a lot of olfactory cells. It should
always secrete mucus to keep the nose moistЈ¬ thus it can transmit all kinds of
olfactory information to the brain.Correct Answer: 2
Why does a dog start barking after it hears the sound of a harmonica?1. It is
extremely sensitive to the sound of a harmonica and barks in enjoyment. 2.It
will bark after hearing sounds of higher frequency.3.It barks in alarm as soon
as
it hears a sound.Key ExplanationЈє The high frequency sound of a harmonica is
similar to the sound of a dog. So dogs canЎЇt help barking as soon as hearing
the
high frequency sound.Correct Answer: 2
Can circus puppies really add and subtract numbers?1.They can make out the
answer
using hints from their owner.2.Because the questions are all the sameЈ¬ they can
remember the right answers.3.They can understand numbers after being trained for
a long time.Key ExplanationЈєAfter being trained for a long timeЈ¬ the puppies
know how many times they must bark at which number with a certain action. So
they
bark at the sight of the numbers.Correct Answer: 3
Why doesn't a dog bark when looking into the mirror?1.Because barking is used to
alert others.2.Because it can not smell any scent.3.It dares not bark after
being
frightened.Key ExplanationЈєBecause of its very sensitive noseЈ¬ a dogЎЇs sense
of
smell is better than its eyesight. So when looking into the mirrorЈ¬ it is
surprised to smell nothing. It will not bark if it thinks there is nothing
around
it.Correct Answer: 2
Why does the wolf like to howl at night?1.In factЈ¬ it howls both in the day and
at night.2.It's the cry of an alert guard-wolf.3.Because the wolf is usually
active at night.Key ExplanationЈєWolves always move at nightЈ¬ looking for food.
They gather together by howling.Correct Answer: 3
Do a catЎЇs whiskers have a special function?1.They can clear away obstacles
that
may be in front of the cat as it moves.2.They can feel for the existence of
other
animals at night.3.They can detect obstacles around the catЈ¬ even in the
dark.Key ExplanationЈєThe catЎЇs whiskers can detect obstaclesЈ¬ letting it know
when to jump instead of pacingЈ¬ and how to move back and forth between two
objectsЈ¬ etc. Without whiskersЈ¬ the cat would have problems moving. For these
reasonsЈ¬ whiskers are very important to the cat.Correct Answer: 3
How is the cat able to jump down from a high place without being injured?1.With
four robust legsЈ¬ it is not easy for it to be injured.2.Because it has soft
muscles to protect itself.3.Because it has an excellent sense of balance.Key
explanationЈєThe cat is good at jumping and climbing. When falling down from a
high place Ј¬ it can quickly balance its body in order to land safely.Correct
Answer: 3
Why does a catЎЇs hair stand on end when it is angry?1.It does this in order to
frighten its enemy.2.It does this because of fear.3.Its hair is a kind of
weapon.Key ExplanationЈєThe cat wants to look more intimidating before a
struggle. All of its body hair stands on end to make itself look bigger. When it
comes across its enemyЈ¬ its skin will become tautЈ¬ enabling its hair to become
erect.Correct Answer: 1
Why does the male cat sing to the female one?1.Because the male cat is afraid of
the female one.2.Because the male cat wants to show its love for and attract the
female cat.3.To frighten the female one.Key ExplanationЈєAll animals can make
criesЈ¬ most of which express hunger or danger. The cry of the male cat is
especially strange and high because it is used to find a partner to mate. The
soundЎЇs purpose is to attract female cat.Correct Answer: 2
Why is the ox always chewing?1. Because it chews the cud.2. In order to keep its
teeth healthy.3.The ox must masticate grass for a long time because of the great
amount of fiber in itKey ExplanationЈєThe ox is a ruminated animal with four
stomachs. It can repeatedly chew the cudЈ¬ letting food into different stomachs.
ThatЎЇs why it is always chewing.Correct Answer: 1
Will the ox be angry at the sight of red?1. The ox becomes angry at the sight
of something wavingЈ¬but in fact it canЎЇt distinguish colors.2. The color red
can
arouse in the ox a of strong consciousness of danger3. The ox is angered because
it sees the keen sword in the hand of the matador.Key ExplanationЈєThe ox canЎЇt
discern colors. Waving anything before it will arouse in it a strong
consciousness of dangerЈ¬ then it will rush to the object excitedly. The matador
uses red cloth only to attract the audienceЎЇs attention.Correct Answer: 1
Do the teeth of a horse have any relationship to its age?1.YesЈ¬ they grow in
length and number as the horse ages.2.There is no particular
relationship.3.YesЈ¬
as the horse grows taller its teeth will grow longer.Key ExplanationЈєHorse Ј¬
oxenЈ¬ sheep and deer are all herbivorous animals. The biggest difference
between
the horse and the rest is that the number of teeth that a horse has increases
with its age. A horseЎЇs teeth will not stop growing until it is five years
old.Correct Answer: 1
Why does the horse often wave its ears?1.The horseЎЇs ears are the organs best
suited to express emotion.2.The ears are used to drive away the annoying
mosquitoes around the horseЎЇs head.3.They are used to help radiate heat.Key
ExplanationЈєBesides being used to hearЈ¬ the horse uses its ears to express all
kinds of emotions. We can tell the feelings of a horse by watching its
ears.Correct Answer: 1
Can an old horse really tell directions?1.It can recognize the way home by using
its sense of smell.2.Its capability of memorizingЈ¬ discerning directionsЈ¬ and
judging is better than other animals.3.It makes marks along the road by
urinating
to find the right way. Key ExplanationЈєCompared with other animalsЈ¬ the horse
has a strong capacity for memorizingЈ¬ discerning directionsЈ¬ and judging. It
can
recognize the road that it has passed through easily.Correct Answer: 2
Does the camelЎЇs hump have a special function?1.It stores fatЈ¬ which is
important in helping the camel to live in the desert.2.It has no particular
function.3.The camelЎЇs stomach is in the hump.Key ExplanationЈєIt is not easy
for
a camel to find food in the desert. Its hump is able to store fat for long
periods of time. ThatЎЇs why the camel can live for a week without eating
anything.Correct Answer: 1
How does the camel find water in the desert?1.It can see the water source with
its good eyesight.2.It can remember the places where it has drunk water in the
past.3.Its olfactory cells can smell water.Key ExplanationЈєA lot of olfactory
cells are distributed in the muscles of the camel. They can be used to look for
the food and water. They can detect moisture even over a long distance.Correct
Answer: 3
Why doesnЎЇt the camel sweat?1. Because it has no sweat gland.2.Its temperature
will increase with the air temperature.3.Its sweat gland has degenerated after
adjusting to life in the desert.Key ExplanationЈєThe camel does not sweat on hot
days. This is in fact related to its temperature. Its temperature changes in the
morning and at night. It sweats less at night because of the high temperature.
This helps to lessen moisture loss from the inside of the camelЎЇs body.Correct
Answer: 2
Why isnЎЇt the camel afraid of sand blown by the wind?1.Because of the dense
hair
on its body. 2.Because its tear gland is developed.3.Because its eyelashes and
nose are very effective.Key ExplanationЈєThere is valve-like organ in the nose
of
the camelЈ¬ which can open and close the nose to resist the sand blown by the
wind. Its double decked eyelashes can easily prevent sand from entering its
eyes.Correct Answer: 3
Can mules have a baby?1.Mules are infertile because they are mixed-blood
animals.2.Mules can't mate because their sex is unclear.3.Mules can have a
babyЈ¬
but they donЎЇt become pregnant easily. Key ExplanationЈєMules are the hybrid
strain of a horse and donkey. Lacking a certain kind of hormone in its
reproduction systemЈ¬ the male mule can't fertilize the femaleЎЇs eggs and they
will quickly die. So mules canЎЇt reproduce.Correct Answer: 1
Why do monkeys often imitate others?1.To show hospitality.2.Imitating others is
an inherent characteristic of monkeys.3.It shows that they are docile
animals.Key
ExplanationЈєGorillasЈ¬ who are the cleverest animals in the monkey categoryЈ¬
and
whose intelligence is first class among animalsЈ¬ have the ability of
recognizing
and learning. For this reason it is easy for them to imitate others.Correct
Answer: 2
Why do monkeys help pick lice off of each otherЎЇs bodies?1.They arrange each
otherЎЇs hair to show intimacy.2.They are getting rid of dirt.3.Monkeys of a
lower
class must pick lice off the bodies of those of a higher class.Key ExplanationЈє
There are no lice on the bodies of monkeys. They in fact arrange each otherЎЇs
hair to show intimacy. Only those without hostility will do it.Correct Answer: 1
How is the monkey king chosen?1.He is chosen hereditarily.2.He is the one who
can
protect the other monkeys.3.He is selected out of one hundred and trained to be
a
monkey king.Key ExplanationЈєMonkeys are social animals who have a leader called
the monkey king. Only the monkey king can raise its tail. This is the signal of
a
leader. No one can imitate it. The monkey king must have the capability to solve
problemsЈ¬ beat back enemies bravely and protect the safety of others. A monkey
with the above abilities will be supported by others to be the monkey
king.Correct Answer: 2
Why doesnЎЇt the rabbit eat the grass around its den?1.It will eat the grass if
it
tastes delicious.2.The grass near the den usually tastes bad.3.The rabbit needs
a
place to hide itself.Key ExplanationЈєA rabbit excretes a substance on the grass
surrounding its den to indicate its sphere of influence. If it eats up the
grassЈ¬ it canЎЇt avoid attack from its enemy.Correct Answer: 3
Why are the ears of rabbits big and long?1.They can help fanning and radiating.
2.They can help locating enemies in time.3.They can push the grass aside and act
easily.Key explanationЈєThe rabbit has no ability to attack and harm other
animals. It can only jump and run away. So it must often erect its ears to
notice
movement all around.Correct Answer: 2
Why are the eyes of a white rabbit red?1.ItЎЇs the color reflected by blood in
its
eyeballs.2.Because it likes eating red radish, which is full of red
pigment.3.Because it has a disease, which makes its eyes red.Key ExplanationЈє
Rabbits have different color eyes because of different pigments in their bodies.
The white rabbit has no pigment in its body. The red color is in fact a
reflection of the blood in its eyeballs.Correct Answer: 1
How does the rabbit avoid its enemy?1.It can jump far and quickly.2.It can send
out a smell to repel the enemy.3.It has a useful protective color.Key
ExplanationЈєThe rabbit usually lives on the open plain. When in dangerЈ¬ it
will
run away from the dangerous area with its excellent jumping ability.Correct
Answer: 1
Why does rabbit make several dens at once?1.It builds only one den with several
entries.2.It builds several dens.3.It builds three dens.Key ExplanationЈєIn
factЈ¬
the rabbit does not make many the dens to avoid attack of its enemy. UsuallyЈ¬
there are many entries for it to flee in case of emergency.Correct Answer: 1
How does a frog prey on mosquitoes?1.It can change its body color to lure
mosquitoes closer.2.It can secrete mucus to seduce mosquitoes.3.ItЎЇs good at
jumping and using the mucus on its tongue to catch mosquitoes.Key ExplanationЈє
There are two methods that the frog commonly uses to catch injurious insectsЈє
Jumping capture and tongue-rolling capture. In the latter methodЈ¬ the mucus on
its tongue is used to catch mosquitoes.Correct Answer: 3
Where do frogs mate and spawn?1.They mate on the bank and spawn in water.2.They
mate in the water and spawn on the bank.3.Frogs seem to mate and spawn in the
waterЈ¬ but in fact they carry out external fertilization.Key ExplanationFrogs
seem to mate and spawn in the waterЈ¬ but in fact they carry out external
fertilization. When matingЈ¬ the male frog rides on the back of the female oneЈ¬
embracing its body tightly. After being stimulatedЈ¬ they will emit ovum and
semenЈ¬ then fertilization will be finished in water.Correct Answer: 3
Why doesnЎЇt the tail of the tadpole disappear after it grows up?1.The tail
can't
easily be found because it has grown smaller.2.It degenerate because it is
useless.3.It changes into the hind legs of the frog.Key ExplanationЈєThe little
tadpole needs to twist its tail to help swimming. During its growth periodЈ¬ its
four feet grow up while its tail gradually degeneratesЈ¬ eventually
disappearing.Correct Answer: 2
Why are the frogЎЇs cheeks constantly rising and shrinking?1.It's the way the
frog
breathes.2.For crying loudly.3.It's a means of saying hello.Key ExplanationЈє
Rising and shrinking its cheeks is the frogЎЇs unique way of breathing. The air
in
its mouth can be beaten into the lungЈ¬ like a pumpЈ¬ while breathing.Correct
Answer: 1
How do you tell apart a frog and a toad?1.1.Frogs often live in ponds while
toads
live in swamps.2.2.Frogs often move about after rainfall while toads are
active
at nigh in the summer.3.The skin of a frog is smooth and looks green or dark-
greenЈ¬ while that of the toad appears dark.Key ExplanationЈєThe most obvious
difference is that the skin of the frog is smooth and looks green or dark-green
while that of the toad appears darker.Correct Answer: 3
How is a frog able to live both in water and on land?1.Because it has a special
breathing organ.2.It can live on land temporarilyЈ¬ but most of the time it
should live in the water.3.It can swim in the water with the ability of holding
its breath for a long time.Key ExplanationЈєBecause the frog has a special
breathing organЈ¬ it is able to live both on land and in the water. When a young
tadpoleЈ¬ the frog breathes in the water using gills and can move quickly using
a
tale. When it maturesЈ¬ the frogЎЇs gills disappear and it breathes using lungs.
The frogЎЇs legs become strongerЈ¬ enabling it to move on land. But the frog
still
keeps its webbed toesЈ¬ which allow it to swim in the water.Correct Answer: 1
How can a snake crawl so quickly without legs?1.The skin can secrete mucus to
increase the speed of crawling.2.The outside scales can erect when crawling in
the shape of an Ў®SЎЇ 3.Crawling in the shape of the letter Ў®SЎЇ can enhance
power
and traction.Key ExplanationЈєWhen crawling in the shape of the letter Ў®SЎЇЈ¬
the
outside scales will raise a littleЈ¬ the tip of which can improve the snakeЎЇs
moving speed.Correct Answer: 2
How can a snake swallow objects bigger than its body?1.It has flexible ligaments
in its mouth.2.It can excrete acid in the mouth to digest the food
immediately.3.There is a square bone in the snakeЎЇs mouth which lets it open
its
mouth widely.Key ExplanationЈєBecause of a square bone in its mouthЈ¬ a snake
can
swallow food much bigger than its body. The bone can open its mouth widelyЈ¬ and
the gullet and stomach can expand with the size of the food.Correct Answer: 3
How does the tail of a rattlesnake make sound?1.The "Horn-wheel" at the end of
the rattlesnakeЎЇs tail can make sound as a small bell.2.The sound is caused by
the air entering into the "Horn-wheel" at the end of the rattlesnakeЎЇs
tail.3.As
the rattlesnake crawls it sways and beats the ground with its tailЈ¬ producing
the sound.Key ExplanationЈєAt the end of the rattlesnakeЎЇs tail there are
several "Horn-wheels"Ј¬ which are hollow inside. They can make sounds due to the
entry of air as soon as the snake waves its tail. In additionЈ¬ one extra "Horn-
wheel" will be added after the snake sheds its skin.Correct Answer: 2
How do you tell apart a viper and the common snake?1. 1.The viper has poisonous
teeth and its head usually is in the shape of a triangle.2.The viper has an
organ
to make sound.3.The skin color of the common snake is more glaring.Key
ExplanationЈєThe basic dissimilarity is whether it has poisonous teeth or not.
FortunatelyЈ¬ we can also judge according to the snakeЎЇs appearanceЈ¬ since it
is
not easy to see its teeth. Generally speakingЈ¬ the head of viper is bigger and
triangularЈ¬ and the streaks are more glaring. You 'd better get away
quickly.Correct Answer: 1
Is a bat a kind of bird?1 1.NoЈ¬ its predecessor is a mouse.2.YesЈ¬ because it
has
wings.3.ItЎЇs a kind of mammal instead of a bird.Key ExplanationЈєThe bat is a
kind of small animalЈ¬ belonging to the mammal family. It has four limbsЈ¬ but
the
front ones have degenerated. It is a viviparous animal with soft hair on its
bodyЈ¬ which is the same as other mammals.Correct Answer: 3
Why do bats hang upside down?1 1.They can fly away at once when in danger.2.They
are not comfortable standing.3.Sleeping upside down can help increase blood
circulation and recovery of physical power.Key ExplanationЈєThe bat is the only
mammal that can really fly. It has wide firm wingsЈ¬ but it can only crawl
slowly
with its hind legs. Hanging upside down in a high placeЈ¬ it can fly away at any
time if in danger.Correct Answer: 1
How does the bat see clearly in darkness?1.It can distinguish directions by
using
its eyesight.2.It can send out sound waves of high frequency with a special
structure known as a "nose-leaf". 3.It distinguishes directions with its earsЈ¬
as does a cat.Key ExplanationЈєWhen flyingЈ¬ the bat can send out sound waves of
high frequency with a special structure called a "nose-leaf"Ј¬ located on its
head when flying. The sound waveЈ¬ which people can't hearЈ¬ is reverberated if
something is ahead of it. So the bat can avoid obstacles easily in spite of
darkness.Correct Answer: 2
Are there any special characteristics in the mating behavior of foxes?1.The male
fox will smear a secretion on the hair of the female one to compel it to
submit.2.Before matingЈ¬ the male fox will do some actions near the female ones
to please them.3.The male fox will force the female one to submit.Key
ExplanationЈєBefore matingЈ¬ foxes will stand up on their hind legs to play a
kind
of Ў°gameЎ±. The male fox will smear a secretion on the body of the femaleЈ¬ the
smell of which will make the female excited.Correct Answer: 1
Why does the fox perform strange Ў°attraction behaviorЎ±?1.In order to get the
attention of the opposite sex.2.In order to gain compassion.3.To fool its
prey.Key ExplanationЈєSometimes the fox pretends to be crazyЈ¬ doing some
strange
actions like wallowing and turning somersaults. Birds and rabbits can't help but
come to see. The fox suddenly stops its performance and preys on them.Correct
Answer: 3
What is the function of the dog-ear foxЎЇs large ears?1.They can aid in hearing
and radiating heat.2.They have no special use3.They can help in fanning and
radiating heat.Key ExplanationЈєIn the hot desertЈ¬ the dog-ear foxЎЇs big ears
can
help to radiate heat in order to avoid an increase in temperature. They can also
distinguish sounds clearlyЈ¬ helping the dog-ear fox to protect itself.Correct
Answer: 1
What kind of animal likes eating antsЈї1.The fox. 2.The monkey.3.The
anteater.Key
ExplanationЈєAnteatersЈ¬ pangolinsЈ¬ boars and orangutans all like eating antsЈ¬
especially the anteater and pangolin. Ants are their main food. They use their
long tongues and mucus to eat ants.Correct Answer: 3
Why must the mouse constantly spoil objects by chewing on them?1.The mouse wants
to confirm whether the object is edible or not.2.The mouse wants to slow the
growth of itЎЇs front teeth.3.It is a mouseЎЇs nature.Key explanationЈєThere is
a
kind of marrow that is constantly secreted to help the growth of the mouseЎЇs
front teeth. It must often chafe on hard things to reduce the growth of its
front
teeth.Correct Answer: 2
Can the mole fly?1.It can only glide.2.Its furЈ¬ like a wingЈ¬ can help it to
fly.3.It's good at jumping though it can't fly.Key ExplanationЈєThe mole is an
animal with fur. It can balance its body when gliding down from a high place in
a
mountain forest with its flat tail. SoЈ¬ it is skillful at gliding instead of
flying.Correct Answer: 1
How does the south American baby-carrying mouse carry its baby?1.It carries its
baby in its mouth.2.The little one lies on its mother's chest or back.3.It holds
its baby with its front legs.Key ExplanationЈєAlthough the south American baby-
carrying mouse is a marsupial animalЈ¬ it has no baby-pouch. UsuallyЈ¬ the baby
can lie on its mother's chest. After growing upЈ¬ it will ride on the back of
its
motherЈ¬ who can climb quickly in spite of the weight of the baby.Correct
Answer:
2
What does the hedgehog do when it is in danger?1.It runs away.2.It erects its
spine to protect itself.3.It attacks its enemy with its sharp teeth.Key
ExplanationЈєIn order to protect itself when in dangerЈ¬ the hedgehog will
conceal
its headЈ¬ handsЈ¬ legsЈ¬ and other soft parts of its body. It shrinks its body
into a round formЈ¬ like a chestnutЈ¬ and erects its spine to avoid being
attacked.Correct Answer: 2
How can a gecko move on a sheer glass surface without falling? 1.Because it has
many deep furrows on its feet.2.Because there are suction cups on its
feet.3.Because its feet can excrete a kind of mucus.Key ExplanationЈєThe plaits
between the gecko's toes form many deep furrows. Because of the friction between
those deep furrows and the smooth surfaceЈ¬ and because of the geckoЎЇs special
absorption abilityЈ¬ the gecko can move on the surface of glass freely.Correct
Answer: 1
Why are geckos and lizards able to cut off their own tails?1. In order to flee
for their life.2. So their tails donЎЇt influence their ability to move.3.
They shed their tail and grow a new one with the change of seasons.4.
Key Explanation:The broken tails have the ability to regrow. So in an
emergency, geckos and lizards will cut off their tails without hesitation to
save
their lives.Correct Answer: 1.
English
Why do birds always sing songs? 1.To express their emotion.2.It is a kind of
instinct without any meaning.3.To be appreciated by people.Key
ExplanationЈєBirds
express their thoughts and feelings by singingЈ¬ this includes looking for
partners and foodЈ¬ protectingЈ¬ alertingЈ¬ etc. This is the result of long-term
adaptation to circumstance no matter whether the sound is short or complicatedЈ¬
sweet or offensive. It has great significance to the life of the bird.Correct
Answer: 1
Why canЎЇt a bird fall out of a tree?1.Fleshy patches on its claws can grasp the
tree branch tightly..2.Suction-cup like areas on the birdЎЇs claws can grip the
tree branch.3.ItЎЇs specially structured toes can hold the branch tightly.Key
ExplanationЈєThe first toe and three other toes of a bird are comparably longer
and adapted to hold a branch tightly. AdditionallyЈ¬ the toesЈ¬ under the strong
force of the birdЎЇs body weight and with specially structured bones and
ligamentsЈ¬ are able to hold the branch tightly.Correct Answer: 3
Why should little stones and sand be added to the forage of a bird?1.Little
stones and sand can substitute the function of teeth to grind food.2.They can
increase the birdЎЇs resistance to disease.3.They can open up the intestine to
avoid indigestion.Key ExplanationЈєThe majority of birds that eat stones and
sand
are vegetarian. Because they have no teethЈ¬ the food will reach their stomach
directly. The sand and little stones can help to grind up the food and promote
digestion. SoЈ¬ the sand and little stones have the function of teeth.Correct
Answer: 1
Why do different kinds of birds have different kinds of mouths?1.Because of a
difference in food selection.2.Because of a difference in living conditions.3.In
order to produce different sounds.Key ExplanationЈєThe shape of a birdЎЇs mouth
will depend upon the kind of food that it eats. For instanceЈ¬ the mouth of
swallow can open widely to tear up meat easily. The mouth-bag of a pond goose
can
pack a lot of little fish. The long and thin mouth of the humming bird is
convenient to suck honey.Correct Answer: 1
Why arenЎЇt migratory birds tired after flying long distance?1.It has
accumulated
energy by eating a great amount of food before flying.2.Because of its slight
body weight and vigorous metabolism.3.Because of its excellent wings and
outstanding endurance.Key ExplanationЈєMigratory birds depend upon their slight
body weight and metabolism to enable them to fly long distance. The energy it
needs comes from the oxygenation of organic substance. ThereforeЈ¬ after molting
in summerЈ¬ it begins to look for food and store fat to prepare for migration in
autumn and winter.Correct Answer: 2
How can a woodpecker stand vertically on the side of a tree?1.It is good at
chiseling holes.2.It has exceptional balance.3.It has very sharp hooks on its
claws..Key ExplanationЈєThe legs of a woodpecker are short and strong.
ParticularlyЈ¬ two of its toes are forward and the other two are backward. It
can
hold a tree tightly with the sharp hooks on the top of its toes. In additionЈ¬
the two feet holding the branch and the stiff feather on the tail divided into
two bundles become three separate pivots. So it can work vertically on the side
of a tree in balance.Correct Answer: 3
Is there any relationship between the swallow and an edible bird nest?1.The
edible bird nest is the excretion of the swallow in producing eggs.2.In fact it
is the tears of the swallow.3.It is the saliva of the swallow.Key ExplanationЈє
The edible bird nest is the nest of the golden-silk swallow. The material in the
nestЈ¬ which is its salivaЈ¬ is different from the clay used by the common
swallow. It contains colloidЈ¬ lower hydrophyte algaeЈ¬ and small fishЈ¬ which
all
cause it to solidify.Correct Answer: 3
How is a parrot able to speak?1. It can be trained to speak because of its
outstanding memory.2. It can speak after training because of its ability to
organize simple language.3. It can imitate people speaking because of its
tapered and fleshy tongue.4. Key ExplanationЈєThe parrot can speak simple
language by using its tapered and fleshy tongue to repeat a string of syllables
taught by people. The speaking is a kind of imitation instead of a conscious use
of language.Correct Answer: 3
Why does a peacock spread open its tail?1.Male peacocks show off to seek a
partner. 2.Female peacocks want to attract male ones.3.To threaten enemies.Key
ExplanationЈєDuring mating seasonЈ¬ male peacocks compete to show off their
attractiveness. So in the mating seasonЈ¬ at the end of spring and beginning of
summerЈ¬ peacocks in the zoo will open their tails if tourists with beautiful
clothes approach them.Correct Answer: 1
Why do hens cluck after producing eggs?1.As a means of relaxing. 2.To inform
cocks.3.Because of pain.Key ExplanationЈєProducing an egg usually takes ten to
twenty minutesЈ¬ sometimes even four to five hours. So after completionЈ¬ the
hen
will take a long time to rest. Then it clucks to show its pride and motherhood.
At the same timeЈ¬ it is informing the cock.Correct Answer: 2
Why does the hen always peck its egg?1.To help the chick break out from the
eggshell easily.2.It is quite upset on producing such a "bad egg" with too thin
of an eggshell.3.To protest that the cock doesn't give it moderate consideration
and protection.Key ExplanationЈєThe Egg is abundant in calcium. If the henЎЇs
diet
is lacking in bone powder or bony little fish full of calciumЈ¬ the hen will
produce an egg with a thin and soft eggshell. The hen will become irritated and
peck the "bad egg".Correct Answer: 2
Why are the two ends of an egg different sizes?1. The egg is compressed to
be thinner during the period of hatching.2. .It is the result of long-term
evolution because the egg must bump the ground after being produced.3. It
matches the shape of the chicken inside the egg.Key ExplanationЈєThe shape of an
egg matches the shape of the chicken inside. A chicken breaks the eggshell with
its mouth. Except for the force of the head and neckЈ¬ the feet need a pivot
point. The small part of the egg is the pivot. If the egg is too round or longЈ¬
it is difficult to find a pivot. So the egg won't be broken easily.Correct
Answer: 3
Why canЎЇt an ostrich fly?1.The wings of the ostrich have degenerated gradually
after long-term adaptation to life in the desert and grasslands.2.It has no
wingsЈ¬ although it is a bird.3.To provide a more comfortable lifeЈ¬ its wings
have degenerated.Key ExplanationЈєOstriches live in the desert and grasslands of
the southern hemisphere. Besides eating plantsЈ¬ they prey on small land
animals.
Their wings have degenerated after long-term adaptation to their environment.
But
their legs are very strong with two toes forward and thick skin under the feet.
They are not afraid of heat or of sinking into the sand. So ostriches can run
fast instead of flying.Correct Answer: 1
Does a duck feel cold in the water during winter?1.It can change its body
temperature with that of the water.2.The duck gets used to the water
temperatureЈ¬ which isnЎЇt really that cold.3.The duck has a thick layer of fat
and waterproof feathers.Key ExplanationЈє The thick fat and waterproof feathers
of the duck can keep it warm even in low temperatures. At the same timeЈ¬ it
won't be worried about water entering into its body.Correct Answer: 3
Why donЎЇt aquatic birds sink in water?1. 1.Because of their light body
weight.2. 2.Because their feathers are thick and 3. plump with fat
on their surface.4. 3. Buoyancy comes into being by paddling5. water
with webbed toes.Key ExplanationЈєAquatic birds always secrete fat from the back
of their tail root and smear it on their feathers Using their head and mouth .
Air can be stored among the thick and plump feathers to avoid sinking.Correct
Answer: 2
Why do seagulls like to fly along side oceangoing vessels?1.It can be absorbed
in
flying instead of alerting other animals.2.It can take advantage of the airflow
formed by the passage of oceangoing vessels to save energy in flight.3.It can
learn directions.Key ExplanationЈєWind is shaped from the flow of air. When it
comes across obstaclesЈ¬ like an oceangoing vesselЈ¬ the atmosphere will ascend
to
form a strong airflow. The seagull cleverly takes advantage of the strong
airflow to support its body. Thus it can fly lightly in the sky by following
oceangoing vessels.Correct Answer: 2
Why do owls regurgitate what they have already eaten?1.Because they always eat
too much.2.Because the food tastes bad.3.Because their stomach canЎЇt digest the
food.Key ExplanationЈєCarnivorous animals like the owl eat up all of their prey.
After eight to twenty-four hoursЈ¬ the owl will shake its head up and down and
vomit a round object. If you examine it carefullyЈ¬ you'll find bird feathers or
animal hair mixed inside. The owl expels those things that can not be
digested.Correct Answer: 3
English
How do jellyfish attack their enemy?1.With needle shaped objects at the end of
their tentaclesЈ¬ which can excrete anesthetic.2.With arista cells on their
tentacles which excrete poisonous liquid.3.Their tentacles will become as stiff
as needles upon coming across the enemy.Key ExplanationЈєThere are a lot of
arista cells with a prick bursa inside on the tentacles of the jellyfish.
Outside
the prick bursa are prods. When penetrating into the enemyЈ¬ these pricks will
fan out into the body. At the same timeЈ¬ they will excrete poisonous liquid to
anesthetize or kill the enemy.Correct Answer: 2
Why does the holothurian need to hibernate during the summer?1.There is little
food on the seafloor in the summerЈ¬ so the holothurian has to sleep to resist
hunger.2.It has to sleep to avoid attack from outside because there are a lot of
competitors in the summer.3.It has to sleep because it can not bear the high
temperature.Key ExplanationЈєMost living creatures in the sea move up and down
in
the water with the change of temperature. In the summerЈ¬ the surface
temperature
becomes high in strong sunshineЈ¬ and little living creatures on the seafloor
float to the surface of the sea to reproduce. The holothurian has to sleep to
make it through the hungry summer.Correct Answer: 1
Is coral a plant or an animal?1.It is an oreЈ¬ and can be made into
decorations.2.It is a plant shaped like a branch.3.It is a kind of lower
animalЈ¬
belonging to the species coelenterate.Key ExplanationЈєCoral belongs to the
species coelenterate which has inner and outer embryo layers only. It only has
an
opening for eating and excreting. It preys on food with tentacles around the
opening. UsuallyЈ¬ coral is made of a lot of "coral-bugs" connecting each other
into a group shaped like a branch. Coral we see is in fact usually a group of
coral-bugs together.Correct Answer: 3
How does the clam eat things without a mouth?1.It opens its shell for
eating.2.It
uses little pores to take plankton in as food.3.It keeps its life by
accidentally
opening its shell to swallow large amounts of food.Key ExplanationЈєThere are
two
pores running parallel to each other at the end of the shell. They connect with
tiny pipes to keep intimate contact with the outside world even though the shell
can be closed for a long time. The circulation of water brings plankton and
oxygen in to avoid hunger and suffocation.Correct Answer: 2
How does a clam walk?1.It depends upon the flexibility of muscles in its Ў°axe-
footЎ±.2.It moves with the help of seawater and other animals.3.It moves slowly
with tiny meat-feet on both sides of its shell.Key ExplanationЈєThere is a white
meat like axe called the "axe-foot " in the shell with strips of muscles on it.
The clam can walk slowly by flexible movement of these muscles.Correct Answer: 1
15-3.Why does the shell of a clam open naturally after boiling?1.Because colloid
for connection becomes stiff after boiling.2.It loses the ability to close the
shell after boiling.3.The muscle used to close the shell becomes too hard to
expand and contract.Key ExplanationЈєClams open and close their shells with the
closing-shell muscle and ligamentЈ¬ which are in the shape of a cylinder and
commonly called the "dried scallop". The shell can close by contracting the
closing-shell muscle. This flexible ligament will expand and cause the shell to
open after boiling.Correct Answer: 3
Why are there pearls in a shell? 1.Because a special substance
inside the shell will become a pearl after its death.2.It can excrete pearl
substance to surround material taken from outside to produce a pearl. 3.In
factЈ¬
pearls are quite rare among shellfish.Key ExplanationЈєFor self-protectionЈ¬ a
shellfish will excrete pearl substance to surround parasites and foreign matter
which enter into its body. ThenЈ¬ a pearl comes into being after a long
time.Correct Answer: 2
Can clams live in stones?1.NoЈ¬ they can only stay there temporarily to avoid
their enemies.2.Some clams can. They §гan excrete a kind of acid to erode stones
into grottos to live in.3.All clams can.Key ExplanationЈєSome clams can live in
stonesЈ¬ because they can secrete a kind of acid from their feet to corrode and
loosen the stones. Then using their feet and water pipes as a pivotЈ¬ they spin
their shells to rub the stones into grottos.Correct Answer: 2
Why doesnЎЇt a hermit crab live in its own shell?1. It has to change a shell
because its own can't grow up.2.It has to hide itself in the spiral shell for
protection because it has no stiff shell and can't move quickly.3.It lives
together with the spiral shell because they are good friends.Key
ExplanationЈєThe
Hermit crab can't swim like a shrimp and it has no hard shell like a crab. So
the
spiral shell becomes a natural refuge for it. With the growth of its bodyЈ¬ it
will find another more suitable spiral shell to live in. It will even eat the
meat of the spiral shell if it can not find a suitable one for a period of
time.Correct Answer: 2
Why will a crab spit foam after leaving the water?1.It can store water in its
gills. After it breathes air on shoreЈ¬ the water will change into white
foam.2.It produces foam-like water to help it breathe after leaving
water.3.Because of difficulty in breathing.Key ExplanationЈєThe crab will not
die
from dryness because it can store water in its gills. It breathes large amounts
of air on shoreЈ¬ which will be taken in from the two sides of its mouth. The
water in its gills will be spit out at the same time.Correct Answer: 1
Why can a crab only crawl sideways?1.This is safer because its eyes can not look
forward.2.It will tangle itself up if it moves straight ahead.3.Its feet only
can
move up and down because there is no turning joint on its feet.Key ExplanationЈє
Except for a pair of pincers for protection and preying on foodЈ¬ the crabЎЇs
other four pairs of feet are for moving. Each is comprised of seven parts. But
there are no turning joints between two parts. Walking-feet can only move up and
down by moving strips of muscle connecting to outer bone.Correct Answer: 3
Why are the feet of a crab so little?1.Because the feet can grow out only after
the crab molts.2.Some of the feet are particularly small because of its
different
speed of growth.3.Some feet have degenerated gradually because they are seldom
used.Key ExplanationЈєWe can catch a crab by holding its head and the two sides
of its chest with the thumb and middle finger. If we only hold a pincer or
walking-footЈ¬ the crab will clip you or run away by giving up the foot which is
seized. The broken foot can be reproduced. The new one is usually smaller
because
the crab has probably molted several times already.Correct Answer: 1
Where does the hair-crab like to live in winter?1.It will go back to the sea in
winter because rivers will freeze.2.It will return to the sea at the beginning
of
winter in order to spawn.3.It will return to the sea because rivers suffer from
a
food shortage during the winter.Key ExplanationЈєThe hair crab is a migratory
animal living in water. It is an "amphibious crab" liking both seawater and
fresh
water. It usually mates at the juncture of the river and sea; then it produces
eggs in the sea. The eggs will not be hatched until spring comes. The crab will
stay in the sea until its death after production.Correct Answer: 2
Why do shrimp and crabs turn red after boiling? 1.There is only red pigment left
in their body after boiling.2.Their colorless blood turns red after boiling.3.A
layer of protective colloid becomes red after boiling.Key ExplanationЈєThe color
of shrimp and crabs is mainly due to their pigment cells located in derma under
their shells. Although shrimp have many kinds of pigment cellsЈ¬ red ones are
predominant. After boilingЈ¬ only the red pigment remain. So the body turns
red.Correct Answer: 1
Why does the green turtle break into tears while producing eggs?1.In order to
make the eyes moist to prevent sand entering them.2.To rinse sand out from the
eyes.3.Because of the pain of producing eggs.Key ExplanationЈєThe clever green
turtle knows clearly that it will feel uncomfortable if sand enters into its
eyes. So it breaks into tears first to protect its eyes.Correct Answer: 1
Why is there dark ink in the stomach of a cuttlefish?1.It is used to baffle the
enemy for self-protection.2.Dark juice is an excretion.3.It is an acid used to
digest food.Key ExplanationЈєThere is a black bag in the stomach of the
cuttlefish which stores black juiceЈ¬ which is a kind of protective device for
use in an emergency. The cuttlefish will spray some black ink to contaminate the
surrounding water when coming across an enemy. It can run away easily while the
enemy is confused.Correct Answer: 1
How does a cuttlefish walk?1.By paddling water with its several
tentacles.2.Through the power of "spurting water".3.By paddling water with two
meat-slices which are like fins at the end of its tail.Key ExplanationЈєThe
cuttlefish goes forward through the power of "spurting water"Ј¬ which is
different from other fish. It is very quick because of the great power coming
from "spurting water". It has to absorb water to supplement its energy once the
water in its body has been used up.Correct Answer: 2
Is there blood in the body of a cuttlefish?1.NoЈ¬ it is a kind of animal without
vertebra.2.There isЈ¬ but the blood can not be found easily because it is mixed
in with black succus.3.There isЈ¬ but the blood is colorless because it lacks
red
pigment.Key ExplanationЈєThe cuttlefish has a complete blood vessel structure
with blood in it. The blood in common animals appears red due to its red
pigment.
The blood of cuttlefish is colorless because it has colorless "serum" instead of
red pigment.Correct Answer: 3
Why does an octopus sometimes hide in a grotto?1.The narrow entry of its den in
a
grotto can help in defense.2.It can avoid an attack during mating.3.It has to
hide in the grotto because it can't resist its enemy.Key ExplanationЈєThe
octopus
likes living in grottos or rock crevicesЈ¬ which can supply a good resting place
for it to sleep in daytimeЈ¬ because enemies can't enter through the narrow
entryway. If it can't find a ready-made grottoЈ¬ it will dig a hole at the
bottom
of the sea with shells around.Correct Answer: 1
How does an octopus prey on its victims?1.It uses its countless suckers to
absorb
the victim.2.It can catch the victim by moving its feetЈ¬ which are very
agile.3.It spurts out dark ink to anesthetize its victim.Key ExplanationЈєThe
octopus can change its body color depending upon circumstances. It can disguise
itself to cheat the enemy and victim. It will appear suddenly to grasp the
victim
tightly when it finds it. The countless suckers on its feet can hold the victim
strongly.Correct Answer: 1
Do fish need to sleep?1.They like sleeping amongst aquatic plants and
rocks.2.YesЈ¬ but it is difficult to distinguish whether they are sleeping or
not
because they have no eyelids.3.They don't need to sleep.Key ExplanationЈєIt is
difficult to distinguish whether fish are sleeping or not because they have no
eyelids. Generally speakingЈ¬ they stop moving when sleepingЈ¬ but still wave
their gill coverЈ¬ dorsal fin and tail to keep balance. AdditionallyЈ¬ their
sleeping time is shortЈ¬ and they are very alert when sleeping.Correct Answer: 2
What purpose does mucus on the scales of a fish serve?1.To prevent salt from
entering into the fishЎЇs bodyЈ¬ resulting in death.2.It has the function of
protecting the fish and reducing friction in the water to make the fish swim
easier.3.Mucus can prevent the loss of body temperatureЈ¬ since the fish is a
temperature-changing animal.Key ExplanationЈєThe mucus all over a fishЎЇs scales
can reduce its friction in waterЈ¬ which makes the fish swim more effortlessly.
At the same timeЈ¬ it protects the fish from attacks by parasitesЈ¬ and bacteria
as well as other microorganisms. It also helps by not allowing harmful
substances
through the permeable skin of the fish.Correct Answer: 2
How can we judge the age of a fish from its scales?1.Count the number of
scales.2.Observe the size of the scales.3.Count the number of thinner pieces of
fish scales.Key ExplanationЈєMost fish already have scales when they are one
year
oldЈ¬ according to the regular growing pattern of fish. Every scale is composed
of many thinner pieces of different sizes. Older fish have thinner pieces
characterized as suchЈє middle layers thickЈ¬ outer one thinЈ¬ top one small.
Younger fish have thinner piecesЈ¬ the lowest layer being the biggest. Thinner
pieces will grow in number with the growth of the fish.Correct Answer: 3
Does every kind of fish have the same number of bones?1.The number of bones
varies with the size of the fishЎЇs body.2.Sea fish have more bones than fresh
water ones.3.The more evolved a fish isЈ¬ the fewer the number of bones that it
will have.Key ExplanationЈєThe number of bones an animal will have will get
fewer
along with the extent that it has evolved. For instanceЈ¬ the bonito has 159
head
bones compared to man's 23. So more evolved fish have fewer bones. Take for
example the yellow fish. Less evolved fish have more bonesЈ¬such as the
bonito.Correct Answer: 3
Can we determine the sex of a fish from its shape?1.Yes. Male fish have a
brighter body color during mating season.2.Yes. The position of the stomach is
differentЈє maleЎЄleft sideЈ¬ femaleЎЄright side.3.No. They are the same.Key
ExplanationЈєThere are over 20Ј¬000 kinds of fish. Although in some species the
sex can be discerned easily by the fishЎЇs shapeЈ¬ the majority of them have no
sex-distinguishing features. But during the mating season male fish will become
brighter in color.Correct Answer: 1
Why do fish gather around an ice-hole?1.For warmth.2.For breathing.3.For
companionship.Key ExplanationЈєThe reason that fish gather around an ice-hole is
that the water nearby can dissolve oxygen from the air for the fish to breathe.
When a lake is freezingЈ¬ the bottom water will be short of oxygen firstЈ¬ the
upper water later becoming so. Fish will find it hard to live in the bottom
waterЈ¬ so they move up and gather around ice-holesЈ¬ which have more contact
with
air.Correct Answer: 2
How do fish sink and float in water?1. Their bodies are full of water.2.Fish
have
streamlined body shapes and special flotation pockets in their bodies.3.They
float and sink depending on the non-stop waving of their gills.Key ExplanationЈє
Fish can sink and float in water because of their streamlined body shape and the
flotation pockets located in their bodies. The air in these pockets comes not
only by breathing with a short pipe while the fishЎЇs head floats above the
waterЎЇs surfaceЈ¬ but also by gills absorbing the air dissolved in plentiful
red
blood cells.Correct Answer: 2
Why will fish die without water?1.Fish can't breathe with gills without
water.2.Fish will die because of dissipation of water in their bodies.3.Without
the supporting buoyancy of waterЈ¬ they can not support their body weight.Key
ExplanationЈєFish can use gills to breathe the oxygen dissolved in water. Gills
can't separate the oxygen from air without water.Correct Answer: 1
Is it necessary for fish to drink even though they live in water?1.Fresh water
fish take in water through the outer skin of film on their gillsЈ¬ while
seawater
fish need to drink a lot of water.2.NoЈ¬ they can absorb water automatically
because their skin is permeable.3.YesЈ¬ they drink when thirsty.Key
ExplanationЈє
Fresh water fish needn't drink to replenish water because water can permeate
into
their body through the semipermeable outer skin of their gills because the
density of body fluid is higher than the water nearby. On the contraryЈ¬
seawater
fish must drink a lot of water to replenish water and dispose the unnecessary
salt because the density of salt in seawater is higher than that of the water
inside seawater fish. CommonlyЈ¬ seawater fish lose water in large
quantities.Correct Answer: 1
Why is the color of ornamental fish extremely bright?1.Because of a sudden
genetic change.2.Because of human-controlled breeding.3.The bright color of
ornamental fish is caused by color cells.Key ExplanationЈєThe color of
ornamental
fish is brightЈ¬ because the derma and scales of those fish have color cellsЈ¬
which make their body colorful. Some of them are extremely beautiful. They are
sent to aquariums or gardens as ornamental fish.Correct Answer: 3
Is there a lot of salt in the bodies of seawater fish?1.No, salt-sorting cells
can dispose unnecessary salt out of their bodies.2.Seawater doesn't have much
saltЈ¬ so there is not much salt left in their bodies.3.Fish have a special
digestive system to filter the salt out.Key ExplanationЈєSeawater fish will not
drink much water unless using gills to breathe. NormallyЈ¬ unnecessary salt will
be disposed of from the salt-sorting cells nearby the gill.Correct Answer: 1
Why do carp like to jump in water?1.They are naturally active and like
jumping.2.The are naturally aggressiveЈ¬ and jump to compete.3.They are
naturally
timid and jump because of fear.Key ExplanationЈєMany fish like jumping. Some
fishermen utilize this to catch fish. Fish jump to bypass obstacles and to catch
food quickly or to avoid sudden attack from an enemy. CarpЈ¬ which are naturally
activeЈ¬ enjoy jumpingЈ¬ especially at dusk. Sometimes their jumping is like a
game.Correct Answer: 1
Why do whales swim back to the Antarctic every year?1.Whales are not afraid of
the coldЈ¬ they like the Antarctic.2.Whales swim to the Antarctic to avoid
capture by humans and pollution.3.In the spring and summer of every yearЈ¬ there
will be a lot of shrimp and fishЈ¬ which whales like to eatЈ¬ in the
Antarctic.Key
ExplanationЈєThere will be a lot of plankton in the Antarctic in the spring of
every year. Plankton is the best food for black-eyed shrimpЈ¬ which is the best
food for the whale to eat. But in autumnЈ¬ it's not suitable for living
creatures
to grow at the low temperature. Whales swim back north due to the shortage of
food.Correct Answer: 3
Why will a whale die on land?1.Because of excessive loss of water.2.It is not
suitable to life on land.3.Its skeleton can't sustain its huge weight on landЈ¬
and its internal organs will be crushed.Key ExplanationЈєThe reason that a whale
can't live on land is not relevant to its lungs. There is no water-floating
force
to share the huge weight of its body on land. Internal organs are stressed too
muchЈ¬ which causes difficulty of breathing and blood-circulationЈ¬ and even
death.Correct Answer: 3
Why do globefish plump up their stomachs?1.To frighten the enemy.2.For
beauty.3.This is caused by the extremely huge flotation pocket in its body.Key
ExplanationЈєThere is a backward air pocket beneath the front of its intestines.
When it is under attackЈ¬ it will float quickly to the water surfaceЈ¬ open its
mouth and engulf air to fill the air pocket. This is a method to protect itself
from being swallowed or hurt by the enemy.Correct Answer: 1
How is the numbfish able to release electricity?1. It has stronger electricity
than other animals have.2.It lives in the sea with electricity.3.It can't
release
electricity. It releases a kind of venomous liquid that when touched produces an
electric shock.Key ExplanationЈєThe cause of electricity is the combination
ofions with positive charge together with an ions with negative charge. Animals
and plants have both ions that cause electricityЈ¬ the majority of which are
feebleЈ¬ while the numbfish's are strong.Correct Answer: 1
Does the male seahorse really give birth to the baby seahorse?1.The seahorse is
unisexual.2.The female seahorse sends the egg to the breeding-bag of the male
for
hatching.3.The female seahorse places the egg into the stomach of the male for
hatching.Key ExplanationЈєTo avoid being eaten by other sorts of fishЈ¬ the
female
seahorse sends the egg to the breeding-bag of the male. At this timeЈ¬ the
embryo
gets necessary nutrition by a thick web of blood vessels. The male seahorse
begins to give birth to its baby after it grows sufficiently in the breeding
bag.Correct Answer: 2
How does the penguin hatch its egg?1.The father penguin puts the egg on closed
feet and covers it with his stomach.2.It is hatched by the body temperature of
both mother and father penguin embracing it together.3.It is hatched in the
mother penguin's armpit.Key ExplanationЈєPenguins don't build a den after
producing an egg. The female penguin looks for food in the sea immediately. At
this timeЈ¬ the well-fed male closes its feetЈ¬ puts the egg on them with his
mouth and then covers the egg with its stomach. It will hatch the egg without
eating and drinking until the female comes back.Correct Answer: 1