Question. Mammals can also generate little bursts of heat through what?
Options:
- (A) Movement of an air mass
- (B) crackling
- (C) Veins and arteries.
- (D) electromagnetic energy
- (E) house
- (F) fire
- (G) muscle contractions
- (H) aerobic capacity
Answer. (G)
What step-by-step reasoning justifies that answer?

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Reasoning: Mammals can also generate little bursts of heat by shivering. Shivering causes muscle contractions to warm the body. Mammals can also generate little bursts of heat through muscle contractions.