The correct answer is A. Amphibians.
Aestivation is a state of dormancy in animals that occurs during hot and dry weather. It is a physiological adaptation that allows animals to survive in harsh conditions by reducing their metabolic rate and water loss.
Amphibians are ectotherms, which means that their body temperature is regulated by the environment. During aestivation, amphibians typically burrow into the ground or hide in moist places to avoid the heat and dryness. They reduce their activity level and enter a state of torpor, which is a deep sleep-like state.
Aestivation is a common adaptation in amphibians that live in hot and dry climates. It allows them to survive periods of drought and heat that would otherwise be fatal.
The other options are incorrect because:
- Chimpanzees are primates that live in tropical forests. They do not need to aestivate because they have access to food and water year-round.
- Salmon are fish that live in both freshwater and saltwater. They migrate to freshwater to spawn, and then return to the ocean. They do not need to aestivate because they can regulate their body temperature in both freshwater and saltwater.
- Squirrels are rodents that live in forests and woodlands. They are active year-round and do not need to aestivate.