Receptors detect changes in the environment. For a stimulus to elicit a response, certain cells must have an appropriate receptor. Stimulation of the receptor initiates a specific signal pathway.
Fatty acids only
Acetyl coenzyme A is a biological molecule that is used in biochemical reactions. These biochemical reactions include the breakdown or hydrolysis of protein, carbohydrates and lipid molecules. The hydrolysis of these molecules in the presence of acetyl CoA produces energy and its primary function is fatty acid metabolism.
From what I've learned so far about hibernation and migration...
Some animals migrate to head towards warmer weather and plentiful food.
Some animals hibernate to conserve energy so they can survive the harsh winters with little to no food at all.
I hope this helped you answer your question.
Answer:
breed, while the ones not so well adapted die off.