Final answer:
The water cycle is primarily driven by solar energy from the sun, which leads to evaporation and sublimation of water into the atmosphere, followed by condensation and precipitation, returning water to the Earth's surface.
Step-by-step explanation:
The energy source that drives the water cycle is the sun's energy. This solar energy warms oceans and other surface waters, which results in the evaporation/sublimation of water. This phase change allows liquid water or ice to convert into water vapor, which is deposited into the atmosphere.
Eventually, this water vapor condenses to form clouds. When it's heavy enough to fall, we observe precipitation (like rain or snow), which returns water to the Earth's surface. Once back on the surface, water can follow various paths like subsurface water flow, surface runoff, snowmelt, and streamflow, eventually leading back to oceans or becoming part of the groundwater system.