Any form of water that falls from clouds and reaches Earth's surface.

• A. surface run-off
• B. open water
• C. water cycle
• D. precipitation

Answer: (D)

When moisture in the air condenses and droplets grow too large, gravity pulls them down as precipitation. This includes rain, snow, sleet, and hail—the actual water that falls from clouds to the Earth's surface. Surface run-off is water that moves along the ground after it has reached the surface; it describes movement, not the falling event. Open water refers to bodies like lakes or rivers, not the process of water entering the surface. The water cycle is the entire system of processes (evaporation, condensation, precipitation, and collection) that move water around Earth, not a single form of water reaching the ground. So, the best term for any form of water that falls from clouds and reaches Earth's surface is precipitation.