________, a hormone that triggers feelings of sleepiness, is released at higher levels when you are in dark surroundings.

Question

Quizplus · Accepted Answer

Melatonin is a hormone that is released by the pineal gland in the brain, primarily at night when it is dark. It plays a key role in regulating the sleep-wake cycle and is responsible for making us feel sleepy. The release of melatonin is suppressed by light exposure, which is why we tend to feel more awake during the day and more sleepy at night.

________, a Hormone That Triggers Feelings of Sleepiness, Is Released