Final answer:
The skin participates in the production of vitamin D when it is exposed to ultraviolet radiation, allowing the synthesis of cholecalciferol from cholesterol in the skin.
Step-by-step explanation:
The skin participates in the production of vitamin D when it is exposed to ultraviolet radiation. In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized from a derivative of cholesterol in the skin. This synthesis process occurs when the skin is exposed to UV radiation, allowing the production of vitamin D3 to help with calcium absorption and bone health.