During photorespiration, ribulose biphosphate carboxylase combines with oxygen gas whichresults in lowering the overall rate of:

Explanation

During photorespiration, ribulose biphosphate carboxylase (RuBisCO) combines with oxygen instead of carbon dioxide, leading to a process that releases carbon dioxide and consumes energy, ultimately reducing the efficiency of carbon dioxide fixation. This process competes with the Calvin cycle, which is responsible for carbon fixation in photosynthesis. Thus, the presence of oxygen decreases the overall rate of carbon dioxide fixation.