You are presented with the question "What can generate little bursts of heat by shivering?" and the following answer choices: 
- alpacas
 - bacteria
 - animals
 - polar bears
 - phytoplankton
 - rabbit
 - viruses
 - humans

Now knowing that mammals can also generate little bursts of heat by shivering and polar bears are mammals, choose the best answer.


 

    polar bears     