Which process is driven by solar energy and powers the cycling of water through evaporation and precipitation?

Which process is driven by solar energy and powers the cycling of water through evaporation and precipitation?

• A. Water cycle
• B. Carbon cycle
• C. Nitrogen cycle
• D. Oxygen cycle

Answer: (A)

The water cycle is driven by solar energy, which heats surface water and causes evaporation (and plant transpiration) to rise as water vapor. As this vapor cools, it condenses into clouds and eventually falls as precipitation. This sequence—evaporation, condensation, precipitation, and movement of water through the atmosphere, surface, and ground—continually recycles Earth's freshwater. The other cycles—carbon, nitrogen, and oxygen—involve chemical and biological transformations and transfers among sinks, but their driving processes are not the evaporation-and-precipitation cycle.

The water cycle is driven by solar energy, which heats surface water and causes evaporation (and plant transpiration) to rise as water vapor. As this vapor cools, it condenses into clouds and eventually falls as precipitation. This sequence—evaporation, condensation, precipitation, and movement of water through the atmosphere, surface, and ground—continually recycles Earth's freshwater. The other cycles—carbon, nitrogen, and oxygen—involve chemical and biological transformations and transfers among sinks, but their driving processes are not the evaporation-and-precipitation cycle.