The ____ produce(s) ____, which influences biological rhythms and the onset of sleep.

A) pituitary gland; thyroid stimulating hormone
B) pituitary gland; adrenocorticotropic hormone
C) pineal gland; melatonin
D) adrenal cortex; cortisol
E) parathyroid glands; parathyroid hormone

Pineal Gland

A small endocrine gland in the brain that produces the hormone melatonin, involved in regulating sleep-wake cycles.

Melatonin

A hormone secreted by the pineal gland that plays a role in setting circadian rhythms.

Biological Rhythms

Natural processes that cyclically change over a period of time in living organisms, such as the circadian rhythm or menstrual cycle.