Water cycle is also called hydrological cycle. In this cycle water moved continuously above the surface of the earth for the continuity of life. Water is evaporated from the sea and ocean in the process of evaporation. This water goes to the atmosphere and form clouds. These clouds moves to hilly areas and comes to the ground in the form of rainfall and snowfall etc. Some water is stored on the mountains in the form of snow and the remaining downward through streams.
"<span>The genes for melanin pigmentation remain turned on and prepare more melanin than usual to protect the skin from photo-damage when it is exposed to sunlight for long time" is the actual reason. </span>