Precipitation is condensed water that falls from the sky. It comes in all shapes and sizes, including ice balls called hail, tiny ice crystals that fall as flakes of snow, sleet or freezing rain and just plain rain. When the drops hit the Earth, everything that was dried by evaporation is again soaked with fresh water - your skin, the roots of trees and plants, and the Earth itself, becoming groundwater that flows into wells and underground streams. What can't soak into the ground forms runoff water, which is how lakes, rivers and oceans are refilled. This water cycle of evaporation, condensation and precipitation repeats, recycling fresh water into the atmosphere, replenishing the ground and allowing plants to grow and animals to survive. It also erodes the Earth's surface, washing away soil, causing occasional floods and slowly changing the face of the land. Which of the following is not a form of precipitation? A groundwater B balls of hail C sleet D snowflakes