TOEFL Listening: TPO-TOEFL听力TPO - WNU250Y5W8789932R$

What does the professor emphasize about the metabolic rate of ectotherms? A. It is regulated by taking short, quick breaths. B. It varies throughout the day. C. It is much slower than the metabolic rate of endotherms. D. It increases to help the animals survive a sudden drop in temperature.