Question

Secretion of ________ from the pineal gland peaks at night and declines during the day.

A) melatonin
B) melanin
C) carbon dioxide
D) glucose

Answer 1

The secretion of melatonin from the pineal gland peaks at night and declines during the day.

Step-by-step explanation:

The correct answer is melatonin (option A).

The pineal gland is an endocrine gland located in the brain that produces and secretes the hormone melatonin. Melatonin is involved in regulating biological rhythms, particularly the circadian rhythm, which controls the sleep-wake cycle. The secretion of melatonin from the pineal gland peaks at night and declines during the day.