What is the waste product of photosynthesis?

The waste product of photosynthesis is oxygen. During photosynthesis, plants absorb carbon dioxide and water and use them to produce glucose and oxygen. While the glucose is used by the plant as a source of energy and to build new plant material, the oxygen is released into the atmosphere as a waste product. This oxygen is then utilized by other living organisms, including animals and humans, for their own respiration processes, while also contributing to the overall balance of oxygen in the atmosphere.