Assertion(A): Colouration of skin is due to a pigment melanin.

Reason(R): It protects the skin and inner parts from ultraviolet sunrays.

The correct option is A Both (A) and (R) are true and (R) explains (A)
$\bullet$ A pigment called melanin is present in the cells of the epidermis.
$\bullet$ The percentage of melanin decides the fairness or darkness of the skin.
$\bullet$ The color of the skin also depends on the climate. Melanin protects our skin and the inner parts from ultraviolet sun rays.
$\bullet$ People living in hotter climates tend to have more melanin content in their body because it protects the skin from UV rays and hence are darker compared to people living in cold regions.