Which process is part of the carbon cycle?

• A. Nuclear fission
• B. Evaporation
• C. Photosynthesis
• D. Sedimentation

Answer: (C)

Photosynthesis is the process that moves carbon from the atmosphere into living matter. Plants, algae, and some bacteria use sunlight to convert carbon dioxide and water into organic molecules like glucose, effectively locking carbon into biomass and releasing oxygen. This carbon fixation is essential to the cycle because it creates the biomass that respiration, decomposition, and other processes later return as CO2. The other options don’t fit: nuclear fission is a nuclear reaction unrelated to carbon cycling; evaporation belongs to the water cycle, not carbon; sedimentation can store carbon long-term, but the everyday carbon exchange most students learn about is photosynthesis.