You are presented with the quiz "Mammals have a layer of fat under the skin to help keep the body warm in what?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mammals have a layer of fat under the skin to help insulate the body" and "hair is used to insulate and keep the body warm in a large variety of climates". 

So, what's the best answer to the question?


 

    a variety of climates       