Assertion: melatonin's role | /r/HasProperty | key
Facets:
Source sentences:
text: For this reason, melatonin plays a key role in maintaining sleep patterns and regulating other hormones.
text: Melatonin plays a key role in reproductive function and development, and also has antioxidant properties.
text: Often called the sleep hormone, melatonin plays a key role in regulating the body's wake-sleep cycle.