Which of the following statements best describes how the hypothalamus regulates body temperature? A. It stimulates blood vessels to constrict to cool down the body.
B. It stimulates blood vessels to dilate to help the body warm up.
C. It activates shivering to cool down the body.
D. It activates sweat glands to cool down the body.

Choice D would be the correct answer

Explanation:

Both choice A and B are incorrect, because they are switched. The constriction of the blood vessels would reduce blood flow, thereby retaining heat in the warmer areas of the body. And the same idea would be applied to choice B since dilating the blood vessels would lead to an increased blood flow near the warm parts of the body, and would cool it down. However, the choices state that the constriction of the blood vessels will cool down the body, which is incorrect.

Choice C is incorrect as well, since shivering would warm up the body, rather than cooling it down. Thus, through the process of elimination, choice D would be the correct answer.

As to how choice D works, the hypothalamus directs the sweat glands to release sweat. The body cools down through the evaporation of the sweat, which would lead to a cooler internal body temperature.