Read the passage below and answer the questions that follow. Passage I

Hibernation

Hibernation is one of the main adaptations that allow certain northern animals to survive long,

cold winters. Hibernation is like a very deep sleep that allows animals to save their energy when

there is little or no food available. The body functions of ‘true hibernators’ go through several

changes while they are hibernating. Body temperature drops, and the heart rate slows. For

example, a hibernating woodchuck’s body temperature drops by more than 30 degrees Celsius,

and its heart rate slows from 80 to 4 beats per minute! Other true hibernators include the jumping

mouse, little brown bat, eastern chipmunk, and several ground squirrels. Other animals, such as

the skunk and raccoon, are not considered true hibernators, as they wake up in the winter to feed,

and their body functions do not change as much. Since they only sleep for a little bit at a time,

the term dormancy or ‘light sleeping’ is used to describe their behavior. The largest animals to

hibernate are bears. Their heart rate may slow down from a usual 40 –50 beats per minute to 8-

12 beats per minute, but their body temperature changes very little, so they are able to wake up

quickly.

Hibernating animals have a special substance in the blood called hibernation inducement trigger,

or HIT. This substance becomes active in the fall, when the days become cooler and shorter.

When HIT becomes active, the animals start preparing for winter. Some animals store food so

that they can eat when they wake up, and some animals eat a lot in late summer and fall to add

excess fat to their bodies. This fat keeps them warmer and acts as a source of energy while they

are sleeping. Some animals also make changes to the places where they will sleep (dens). They

add leaves and grasses to keep them warm.

Questions: (5×1=5)

Choose the correct alternative.

1. Why do animals hibernate?

A. Animals hibernate to survive long.

B. Animals hibernate to adapt to the temperature.

C. Animals hibernate to save energy during the winter when there is little food for them to

eat.

D. Animals hibernate to take a deep uninterrupted sleep.

2. What changes occur in the functions of an animal’s body when it hibernates?

A. An animal’s body temperature and its heart beat rise when it is hibernating.

B. An animal’s body temperature drops and its heart beat quickens when it is hibernating.

C. An animal’s body temperature drops and its heart beat slows when it is hibernating.

D. An animal’s body temperature drops and its heart beat remain constant when it is

hibernating.