Question

may notice that they feel better when the sun is
shows that staying in the sun for 15 to 20
an improve human health. sunlight causes the
erotonin, a chemical that helps people’s moods.
of sunlight is that people absorb vitamin d from it.
thens bones and teeth. also, staying in the sun for
tes a week causes the body to make melatonin.
chemical that helps people sleep at night.
light is harmful to people. staying in the sun for
se the skin to burn. also, too much sunlight is
skin diseases. people should limit their time in the
e in the sun for lengthy periods of time, they
screen and/or protective clothing to prevent
rom the sun.

2
according to the passage, what causes bones and teeth to get stronger?
a. serotonin
b. melatonin
c. sleep
d. vitamin d

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Explanation:

To solve this, we analyze the passage. The relevant sentence is "Sunlight causes the body to absorb vitamin D from it. Also, staying in the sun for [time] strengthens bones and teeth." So we check each option:

• Option A: Serotonin is related to moods, not bones/teeth. Eliminate.
• Option B: Melatonin is related to sleep, not bones/teeth. Eliminate.
• Option C: Sleep is not a substance causing bones/teeth to strengthen. Eliminate.
• Option D: The passage says sunlight helps absorb vitamin D, which strengthens bones and teeth. This matches.

Answer:

D. vitamin D