What energy source powers the water cycle?

• A. Wind
• B. Geothermal energy
• C. Nuclear energy
• D. The sun.

Answer: (D)

Solar energy powers the water cycle. Heat from the sun warms oceans, rivers, and soil, causing evaporation (and plants add to this with transpiration). The resulting water vapor rises, cools, and condenses into clouds, leading to precipitation that returns water to Earth and keeps the cycle going. Wind and other heat sources aren’t the primary drivers: wind is a movement created by solar heating, while geothermal or nuclear heat can affect local spots but don’t supply the global energy that drives evaporation. So, the sun is the main energy source sustaining the cycle.