Final answer:
Water vapor in the atmosphere cools and condenses into clouds, leading to precipitation such as rain or snow, which returns water to the Earth's surface.
Step-by-step explanation:
Water returns to the Earth's surface primarily through the process of precipitation, which includes rain, sleet, hail, or snow. This cycle begins with the Sun heating water on the Earth's surface, causing it to evaporate or sublimate. The resulting water vapor then rises into the atmosphere, where it cools and condenses into clouds. Eventually, the condensed water falls back to the surface as various forms of precipitation. Once on the ground, this water can flow as surface runoff into bodies of water, like rivers or oceans, or it can infiltrate the soil and enter the groundwater system, contributing to aquifers.