The correct answer is option 'C'. Hibernation.

Definition:
Hibernation is a state of inactivity and metabolic depression in animals during winter. It is a survival strategy used by animals to conserve energy and survive when food resources become scarce during the cold winter months.

Characteristics of Hibernation:
During hibernation, animals experience a significant drop in their metabolic rate, body temperature, heart rate, and breathing rate. They enter a state of deep sleep and their bodily functions slow down to conserve energy.

Key Points:
- Hibernation is a long winter sleep of animals.
- It is a state of inactivity and metabolic depression.
- Animals experience a drop in metabolic rate, body temperature, heart rate, and breathing rate.
- Hibernation helps animals conserve energy when food resources are scarce.

Examples of Hibernating Animals:
Many animals hibernate during the winter months to survive. Some common examples of hibernating animals include:
1. Bears: Bears hibernate in dens during winter, where their heart rate and breathing rate decrease significantly.
2. Ground Squirrels: Ground squirrels hibernate in burrows and their body temperature drops to match the surrounding temperature.
3. Bats: Bats enter a state of torpor, which is similar to hibernation, to survive winter when insects (their primary food source) are scarce.

Reasons for Hibernation:
1. Conservation of Energy: Hibernation allows animals to conserve energy by reducing their metabolic rate and other bodily functions.
2. Scarce Food Resources: During winter, food becomes scarce, and hibernation helps animals survive when there is limited or no access to food.
3. Extreme Cold: Hibernation helps animals withstand extremely low temperatures by lowering their body temperature and entering a state of dormancy.

Conclusion:
Hibernation is a survival strategy used by animals to cope with the harsh winter conditions when food resources are limited. It allows animals to conserve energy and survive until favorable conditions return in spring.

Hi
Sahil