How does the body monitor its core temperature?
a. nerve cells in the skin feed the information to the hypothalamus.
b. the pituitary gland in the brain tracks the temperature of the blood.
c. nerve cells monitor the temperature of the hypothalamus.
d. core blood temperature alters the speed of the chemical reactions in the pituitary gland.
e. core blood temperature alters the speed of nerve cells in the hypothalamus.

A. Nerve cells in the skin feed the information to the hypothalamus.

Explanation:

The hypothalamus is a part of the brain which controls the body temperature. The nerve cells present on the skin sends the signals to the hypothalamus when the body experience warm external temperature, which sends the signals to the sweat glands so that it's secretion makes the body cool. When the body feels cold then the hypothalamus sends the signal to the muscles to produce shivering to keep the body warm.

not only is it colder, it also becomes darker, less salty, and more dense.