What causes the water cycle?

SUN is the biggest engine, which drives all the forces of nature, precipitation is one of such amazing process by nature, through which water returns back to earth. initially water is evaporated from oceans and lands, where oceans contribute 65-70% of total precipitation as evaporation. Once, water is evaporated by energy of Sun, water turns into water vapour and gets condensed in the atmosphere to form clouds, these clouds relaeases water in the form of precipitation in the form of rain or snow (depending local weather conditions). Rain is then intercepted by trees / building cover etc., once rain water reahces the ground, soil absorbs the water untill its saturation point is reached, water from soil then flows as subsurface water or ground water to oceans. water from surface forms channels, channels joins to form rivulets, then to rivers and great rivers, all flows towards ocean. Water again then gets evaporated from oceans and lands to form clouds.

Although ocean contributes maximum of rain, water through evapotranspiration also contributes significant amount. But finally SUN is the most important source of all force in nature.