Which processes are part of the water cycle?

• A. Condensation and evaporation only
• B. Photosynthesis only
• C. Evaporation, condensation, precipitation, transpiration, runoff, groundwater (aquifer)
• D. Precipitation and combustion

Answer: (C)

Water moves through the atmosphere, surface, and underground in a continuous cycle powered by energy from the sun. The cycle includes evaporation, where liquid water becomes vapor; transpiration, when plants release water vapor; condensation, with vapor cooling into droplets; precipitation, when water returns as rain, snow, or hail; runoff, as water flows across the land into rivers and oceans; and groundwater movement, as water soaks into soil and travels through aquifers. Other processes like photosynthesis and combustion aren’t steps of the water cycle themselves—photosynthesis uses water but isn’t a cycle step, and combustion isn’t a water-cycle process. So the full set of processes listed best describes the water cycle.