Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: Mammals generate heat mainly by maintaining a high rate of metabolism. Compared with the cells of other animals, the cells of mammals have more mitochondria. Mitochondria are the cell organelles that generate energy. Mammals may also produce little bursts of heat by shivering. Shivering occurs when many muscles all contract slightly at the same time. The muscle contractions generate a small amount of heat. Answer: maintaining high metabolism
A:
How do mammals generate heat?