what is global hydrological cycle

The hydrological or water cycle is the constant recycling
of water in the earth system.  Water that we drink today is the same water the dinosaurs
drank. The water cycle consists of evaporation, condensation, evapotranspiration, and
precipitation.  Evaporation puts water into the atmosphere by changing liquid water to
water vapor.  This comes from lakes, rivers, and the oceans.  Condensation occurs as
water vapor changes to liquid water in the form of clouds.  Evapotranspiration puts
water into the atmosphere from the plants and trees on earth.  Precipitation returns
water to the surface of the earth.  On the surface of the earth the water may run off
into streams, lakes, rivers, and oceans or may seep into the earth and replenish stores
of groundwater.