I will not have any questions about the moon or early differentiation of the Earth. The hydrologic cycle The abundance of liquid water makes Earth different from all other planets. Most of Earth's water is in the oceans. The image shown at this link illustrates the proportion of Earth's surface water in the several important reservoirs. Most of the fresh water is in polar ice caps and glaciers.
Water is the agent for the interaction between the sun and Earth's surface.
The sun's radiant energy is absorbed by the surface, most abundantly near the equator, where sea water is evaporated. Most of the evaporated water returns to the ocean by direct precipitation in the tropics. Moist air also drifts out of the tropics, precipitates as rain or snow, and either returns to the oceans in streams or in groundwater. This image shows a sketch of the hydrologic cycle , which shows the reservoirs and the transfer of water between reservoirs. Groundwater A large fraction of the Earth's fresh water is actually under our feet, in the ground.