Linked from
The 7 pages that link to Ultraviolet-B, each with the reason it gives.
Ozone depletionBroader topic: Thinning ozone allows more UV-B radiation to reach Earth’s surface.
Vitamin DRelated: It initiates the skin pathway that makes cholecalciferol.
Reptile husbandryRelated: UVB lighting supports calcium metabolism in species that require it.
Chinese water dragonRelated: Appropriate UVB exposure supports calcium metabolism in captive care.