Humans make vitamin D using UV-A from the Sun. We regulate this process by making melanin.
No
ultra violet rays
ultra violet rays Actually, it's spelled ultraviolet rays.
Ultra Violet Rays
ultra violet rays
"ozone"
no
Ultra violet radiation or UV rays are harmful. Ozone protects us from it.
UV rays? or Ultra Violet rays
Ozone layer.
Ultra Violet :D
chlorophyll