Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

The word “defends” in paragraph 2 is closest in meaning to

A. encourages

B. protects

C. feeds

D. pretends

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

The word “paralyzed” in paragraph 1 is closest in meaning to

A. disabled

B. unaffected

C. inaccessible

D. undecided

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

In paragraph 1, why does the author mention the platypus?

A. To illustrate that mammals may eat poisonous plants.

B. To give an example of a mammal that uses poison.

C. To show how it differs from the crested rat.

D. To explain that the platypus is at risk.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What is the main purpose of the passage?

A. To show how animals can affect plant life.

B. To compare one animal to other similar ones.

C. To emphasize the dangers of researching animals.

D. To discuss an unusual animal defense technique.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What are scientists surprised by?

A. How toxic plant poison can be.

B. How useful plant toxins can be.

C. How quickly rats learn new behavior.

D. That the rats are protected from the poison.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

 The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What would scientists like to investigate further?

A. Medicine used to counteract poison.

B. Other animals like the crested rat.

C. Health effects of a chemical.

D. Rats with unhealthy hearts.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions

Certainly no creature in the sea is odder than the common sea cucumber. All living creature, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?

For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to such up mud or sand and digest whatever nutrients are present.

Sea cucumbers come in a variety of colors, ranging from black to reddish-brown to sand-color and nearly white. One form even has vivid purple tentacle. Usually the creatures are cucumber-shaped-hence their name-and because they are typically rock inhabitants, this shape, combine with flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents.

Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate-feeding sparingly or not at all for long periods, so that the marine organisms that provide their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence.

But the most spectacular thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs, when attacked, it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attached or even touched; it will do the same if the surrounding water temperature is too high or if the water becomes too polluted.
Question:According to the passage, why is the shape of sea cucumbers important?

A. It makes them attractive to fish

B. It helps them to protect themselves from danger.

C. It helps them to digest their food.

D. It makes it easier for them to move through the mud.

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each question.

     Certainly no creature in the sea is odder than the common sea cucumber. All living creature, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?

For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to suck up mud or sand and digest whatever nutrients are present.

Sea cucumbers come in a variety of colors, ranging from black to reddish – brown to sand – color and nearly white. One form even has vivid purple tentacles. Usually the creatures are cucumber – shaped – hence their name – and because they are typically rock inhabitants, this shape, combined with flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents.

Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate-feeding sparingly or not at all for long periods so that the marine organisms that provide their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence.

But the most spectacular thing about the sea cucumber is the way it defends itself. It major enemies are fish and crabs, when attacked; it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attacked or even touched; it will do the same if surrounding water temperature is too high or if the water becomes too polluted.

Which of the following would NOT cause a sea cucumber to release its internal organs into the water?

A. A touch 

B. food

C. unusually warm water 

D. pollution

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions

Certainly no creature in the sea is odder than the common sea cucumber. All living creature, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?

For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to such up mud or sand and digest whatever nutrients are present.

Sea cucumbers come in a variety of colors, ranging from black to reddish-brown to sand-color and nearly white. One form even has vivid purple tentacle. Usually the creatures are cucumber-shaped-hence their name-and because they are typically rock inhabitants, this shape, combine with flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents.

Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate-feeding sparingly or not at all for long periods, so that the marine organisms that provide their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence.

But the most spectacular thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs, when attacked, it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attached or even touched; it will do the same if the surrounding water temperature is too high or if the water becomes too polluted.
Question:The fourth paragraph of the passage primarily discusses

A. the eating habits of sea cucumbers

B. the food sources of sea cucumbers

C. the reproduction of sea cucumbers

D. threats to sea cucumbers’ existence