What are the two main drivers of the water cycle?

The two main drivers of the water cycle are the Sun and gravity.

1. The Sun: The Sun provides the energy that drives the water cycle. It heats the water in the oceans and seas. This heat causes the water to evaporate and turn into water vapor, which rises into the atmosphere. This process is known as evaporation.

2. Gravity: After the water vapor cools and condenses to form clouds (a process known as condensation), gravity causes the water to fall back to the Earth's surface as precipitation (rain, snow, etc.). Once the water is back on the surface, it either evaporates again, is taken up by plants (a process known as transpiration), or flows back into the oceans and seas (a process known as runoff). This completes the water cycle.