What is the function of UVA and UVB rays in tanning?

The correct response indicates that UVA rays are associated with the "melanin browning" effect, while UVB rays are recognized for their role in "melanin activation." UVA rays penetrate deeper into the skin and stimulate the production of melanin, which is responsible for the tanning effect. This process leads to skin darkening as melanin absorbs UV radiation, providing a protective barrier against further UV exposure.

On the other hand, UVB rays primarily affect the outer layer of the skin and are essential for initiating the body's natural tanning response by stimulating the production of melanin. They are also involved in the process of vitamin D synthesis, which is crucial for overall skin health.

Understanding these functions helps clarify why this option accurately describes the roles of UVA and UVB rays in the tanning process.