You are presented with the question "Mammals can also generate little bursts of heat through what?" and the following answer choices: 
- Movement of an air mass
 - crackling
 - Veins and arteries.
 - electromagnetic energy
 - house
 - fire
 - muscle contractions
 - aerobic capacity

Now knowing that mammals can also generate little bursts of heat by shivering and shivering causes muscle contractions to warm the body, choose the best answer.


 

       muscle contractions  