Melissa Uses a Sunscreen with an SPF Rating of 20

question 84

Multiple Choice

Melissa uses a sunscreen with an SPF rating of 20.What does this does this mean?

• A)She can stay in the sun for 20 minutes without getting tanned or burned.
• B)She can stay in the sun 20 times longer without getting burned than if she didn't use it.
• C)She is protected against the full range of ultraviolet radiation.
• D)Her sunscreen contains 20 different ingredients to block ultraviolet radiation.

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Definitions:

Pineal Gland

A small endocrine gland in the brain that produces melatonin, a hormone that affects the modulation of wake/sleep patterns and photoperiodic (seasonal) functions.

Melatonin

A hormone produced by the pineal gland that regulates sleep and wakefulness.

Serotonin

A neurotransmitter that plays an important role in mood regulation, as well as in sleep, digestion, and other bodily functions.

Ria

A drowned river valley formed by the submergence of an unglaciated river valley, leading to a long, narrow, winding inlet.