By producing melanin (pigment), the skin protects the underlying structures from ultraviolet light's harmful rays while producing vitamin which works with calcium for multiple body processes.

By producing melanin (pigment), the skin protects the underlying structures from ultraviolet light's harmful rays while producing vitamin D, which works with calcium for multiple body processes.

Vitamin D is produced by the skin when it is exposed to the sunlight. Ultraviolet B (UVB) is the part of the sun's rays that affects the skin to produce such vitamin.