Which of the following is an accurate statement about thermoregulation?
A) Endotherms are warm-blooded and ectotherms are cold-blooded.
B) Endotherms maintain a constant body temperature and ectotherms do not.
C) Endothermy has a lower energy cost than ectothermy.
D) Endotherms and ectotherms differ in their primary source of heat for thermoregulation.
E) Endotherms are regulators and ectotherms are conformers.
Answer: D