What is the skin's primary response to UV rays?

The skin's primary response to UV rays is to protect itself. When exposed to ultraviolet radiation, the skin initiates a series of biological processes aimed at safeguarding its integrity and function. One of the most significant protective responses is the production of melanin, the pigment responsible for the color of skin, hair, and eyes. Melanin absorbs UV radiation, reducing the potential for DNA damage that can lead to skin cancer.

Additionally, the skin may thicken in certain areas (a process called hyperkeratosis) as a defense mechanism to provide an extra layer of protection against further UV exposure. Other responses may include increased blood flow to the area, causing skin to appear red, and activating inflammatory processes to protect against damage.

While burning, moistening, or peeling can occur as skin reactions in response to UV exposure, they are consequences of excessive or insufficient protection rather than the primary defensive mechanism. Therefore, the correct answer emphasizes the skin's innate ability to defend and shield itself from harmful UV radiation.