Hydrologic cycle is the undertaking of water amongst the basins of atmosphere, land and ocean. Water from the ocean enters the atmosphere through evaporation. And the sun helps in the evaporation of water and transpiration form the plants. As soon as it is contained in the atmosphere, the water vapor collects more water vapor, thus forming the dark clouds. When all water vapor form the ocean is collected, the high pressure allows the water vapor to condense and form rain, thus condensation occurs. The soil in most lands collects water from rain and they are held by chemical forces and gravitational surface tension. Then the process is repeated.