Dark skin is found in populations near the equator. why? it protects from the damaging effects of uv radiation on folate. it prevent rickets.

Dark skin is found in populations near the equator because it protects from the damaging effects of UV radiation on folate. People who are living in intense sunshine and heat regions have dark skin pigmentation.
The darker the skin the greater its resistance. The skin color is due  to the presence of a pigment called melanin and this  pigment acts as a protective biological shield against ultraviolet radiation. 

Energy from the Sun is known as Photovoltaic Energy Solar Thermal Energy. !