Question

functions of the endocrine glands
which hormone is associated with the bodys circadian rhythms and sleep-wake cycles?
adrenaline
melatonin
cortisol
parathyroid hormone

Explanation:

Melatonin is a hormone that is secreted by the pineal gland in response to darkness. It helps regulate the body's circadian rhythms (the 24 - hour internal clock) and sleep - wake cycles. Adrenaline (epinephrine) is involved in the "fight - or - flight" response. Cortisol is a stress hormone. Parathyroid hormone is mainly involved in regulating calcium levels in the body.

Answer:

B. Melatonin