You are presented with the quiz "which can help warm-blooded animals stay active in cold?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mammals can also generate little bursts of heat by shivering" and "most mammals can be active even in cold weather because they are warm-blooded". 

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


 

 shivering          