Question

the pineal gland synthesizes which hormone?
o pineal hormone
o serotonin
o dopamine
o melatonin

Explanation:

The pineal gland is known to synthesize melatonin. Serotonin is a neurotransmitter (though it can be a precursor for melatonin synthesis in the pineal gland, but the main hormone synthesized by the pineal gland is melatonin). Dopamine is also a neurotransmitter. There is no "pineal hormone" as a standard named hormone in human physiology. Melatonin is crucial for regulating the sleep - wake cycle.

Answer:

melatonin