You are studying a large tropical reptile that has a high and relatively stable body temperature. Which of the following observations is best for determining if the animal is an endotherm or an ectotherm?
A) You know from its high and stable body temperature that it must be an endotherm.
B) You know that it is an ectotherm because it is not a bird or mammal.
C) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
D) You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.

Question

Quizplus · Accepted Answer

C is correct because ectotherms rely on external sources to regulate their body temperature, and their metabolic rate changes with the ambient temperature. This observation directly assesses the reptile's physiological response to temperature changes, distinguishing it as an ectotherm.

You Are Studying a Large Tropical Reptile That Has a High