When light begins to fade at the end of the day,the suprachiasmatic nucleus in the __________ signals the pineal gland to release __________.
A)hippocampus;melatonin.
B)hippocampus;serotonin.
C)hypothalamus;melatonin.
D)hypothalamus;serotonin.

Question

Quizplus · Accepted Answer

The suprachiasmatic nucleus, which is located in the hypothalamus, is responsible for regulating the circadian rhythm or the "body clock." When light begins to fade at the end of the day, the suprachiasmatic nucleus signals the pineal gland to release melatonin, which helps promote sleepiness. Therefore, the best choice is C, where the hypothalamus signals the pineal gland to release melatonin.

When Light Begins to Fade at the End of the Day,the