This last question involves the endocrine system.
Melatonin (known chemically as N-acetyl-5-methoxytryptamine) is a naturally
occurring hormone found in animals and in some other living organisms, including
algae. Read the material about melatonin in your book that starts on page 74.
Some people take melatonin supplements to help sleep. Products containing
melatonin are available as a dietary supplement in the United States but are illegal in
some other countries. Foods may contain trace amounts of melatonin, but no food
has been found to elevate plasma melatonin levels.
What gland of the endocrine system releases melatonin?
A.pancreas
B.pineal
C.thyroid
D.pituitary