How many times can an enzyme work on a reaction?

Enzymes are not reactants and are not used up during the reaction.

Explanation:

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.

answer; (a) medicalized;