Which process is not part of the hydrological cycle?

• A. Evaporation
• B. Condensation
• C. Photosynthesis
• D. Precipitation

Answer: (C)

The hydrological cycle centers on how water moves and changes state among reservoirs—surface water, soil moisture, groundwater, and the atmosphere. Evaporation drives water from surfaces into the air, condensation forms clouds from that water vapor, and precipitation returns water to the surface. Plants contribute via evapotranspiration, the combined water loss from soil and plant surfaces back to the atmosphere. Photosynthesis, however, is a biochemical process in which plants use light to convert carbon dioxide and water into sugars, with oxygen released as a byproduct. It uses water, but it does not move water through the cycle or involve its phase changes or atmospheric transport. So photosynthesis isn’t part of the hydrological cycle.