The primary role of photosynthesis in the carbon cycle is to convert carbon dioxide from the atmosphere into organic compounds, effectively capturing and storing carbon. This process, performed by plants, algae, and some bacteria, produces glucose and oxygen, forming the foundation of the food web. Photosynthesis helps regulate atmospheric CO2 levels, thus playing a critical role in combating climate change by reducing greenhouse gas concentrations. It also supports energy flow through ecosystems, highlighting its significance in sustaining life.