When _____ levels produced by the pineal gland rise late in the evening, it's bedtime as far as the brain is concerned.
A)melatonin
B)serotonin
C)acetylcholine
D)androgen

Question

Quizplus · Accepted Answer

Melatonin is a hormone produced by the pineal gland, which regulates sleep-wake cycles. Its levels rise in the evening and remain high throughout the night, promoting drowsiness and sleepiness. Therefore, when melatonin levels rise late in the evening, it signals to the brain that it's bedtime. Serotonin is another neurotransmitter that is involved in regulating sleep, but its levels typically decrease in the evening, making it an unlikely answer choice. Acetylcholine and androgen are not directly involved in regulating sleep-wake cycles.

When _____ Levels Produced by the Pineal Gland Rise Late