Multiple choice general knowledge

Exposure to sunlight helps a person improve his health because

  1. the infrared light kills bacteria in the body

  2. resistance power increases

  3. the pigment cells in the skin get stimulated and produce a healthy tan

  4. the ultraviolet rays convert sin oil into Vitamin D
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When skin is exposed to sunlight, ultraviolet B (UVB) rays penetrate the skin and convert 7-dehydrocholesterol (a compound in skin oils) into Vitamin D3 (cholecalciferol). This is the primary way humans obtain Vitamin D, which is essential for bone health, immune function, and calcium absorption. The process is a natural biochemical reaction, not related to bacteria or tanning.

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