Shivering occurs when many muscles contract a little bit all at once.
Involuntary contractions, shivering, cause the production of heat.
The production of heat occurs when many muscles contract a little bit all at once.
What occurs when many muscles contract a little bit all at once?
[A] the production of cells
[B] preventing heat transfer
[C] To keep their body heat.
[D] the production of heat
[E] Generating heat
[F] recovery time from fatigue
[G] the production of cold
[H] the production of skin