Shivering helps to raise body temperature because
- A. rapid involuntary muscle contractions release heat from respiration
- B. it increases the blood flow to the skin
- C. it reduces the surface area of the body
- D. it stops sweat being produced
Explanation
The muscles contract and relax rapidly without doing any useful external work, so almost all the energy released by increased respiration in the muscle fibres appears as heat. The metabolic rate can rise several fold during vigorous shivering. It is a short term emergency response, since it is tiring and depends on the glycogen stored in muscle.