Answer;
-Oxygen
Step-by-step explanation;
Both the glucose and oxygen produced in photosynthesis are used in aerobic respiration.
-Photosynthesis makes the glucose that is used in cellular respiration to make ATP. The glucose is then turned back into carbon dioxide, which is used in photosynthesis.
-While water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.