Which of the following is mentioned about the variety of physiological and behavioral mechanisms an endotherm uses to regulate its internal temperature?
Incorrect.
[[snippet]]The second sentence of the first paragraphs states that in certain circumstances, an endotherm requires increases in heat production, which in turn necessitate increases in metabolism. This answer choice, however, incorrectly states that the opposite is true.
Incorrect.
[[snippet]]The passage does not state that endotherms are always engaged in producing or dissipating heat to compensate for the external temperature but only describes those situations in which they do have to compensate. Therefore, there is no support in the passage for the statement that endotherms do not have a natural, "comfortable" temperature at which they do not have to compensate for the effects of the temperature of the air.
Incorrect.
[[snippet]]The last sentence of the first paragraph states that endotherms produce heat more efficiently than they dissipate it. However, although we know that by dissipating heat an endotherm creates some heat, the passage does not compare the efficiency of that heat production with the efficiency of heat an endotherm produces in order to cope with cold temperatures.
Great!
[[snippet]]The passage explicitly states that the responses used by an endotherm to decrease its body temperature contribute to the situation the animal is attempting to surmount (i.e. a situation in which the endotherm gains heat from the environment).
Incorrect.
[[snippet]]This answer choice goes too far.
The passage states that endotherms cannot dissipate heat as effectively as they can produce it, which does not mean that they cannot dissipate heat at all.