The correct answer is option 2 - Hibernation. Hibernation is a state of reduced activity and metabolism that some animals enter during the winter season. During hibernation, the animal`s heart rate, breathing, and body temperature decrease significantly, allowing it to conserve energy and survive in harsh conditions. The animal goes into a state of dormancy, also known as torpor, and may sleep for an extended period of time without eating or drinking. This adaptation helps the animal cope with cold temperatures and scarcity of food during winter. Aestivation (option 1) refers to a similar state of dormancy, but it occurs during dry or hot seasons. Regeneration (option 3) is the process of regrowing or replacing lost or damaged body parts. Mutation (option 4) refers to changes in the DNA sequence that can lead to varied traits or characteristics.