Answer:
It prevents cancer.
Step-by-step explanation:
UV rays penetrate the many layers of the epidermis, reaching the deep layers of our skin, which is meant to be protected. This activates pigment cells, releasing Melanin and darkening the skin.
When the UV rays penetrate these deep cells, it reacts similarly to radiation, denaturing and breaking apart DNA. If enough damage is done and the cell becomes irreparable a tumor forms.
Consistent exposure to UV rays has detrimental effects because it puts your skin cells through this same stress every day.