Which substance protects the body from ultraviolet rays?

Keratin is a structural protein that forms the outer layer of skin, hair, and nails, providing strength and protection. However, keratin does not actively absorb UV rays; instead, its primary function is to create a barrier against physical and chemical damage, making it less effective in UV protection compared to melanin.

Sebum is an oily substance produced by sebaceous glands that helps to lubricate and waterproof the skin and hair. While it plays a role in maintaining skin hydration and barrier function, it does not absorb ultraviolet light or provide sun protection, making it inadequate for defending against UV radiation.

Perspiration, or sweat, regulates body temperature through evaporation and helps to maintain skin hydration. Although it may provide a slight cooling effect, perspiration does not provide any significant protection against UV rays, as it does not contain properties that absorb or block ultraviolet radiation.