For what purpose does a plant use the sugars produced during photosynthesis

Photosynthesis is the process by which green plants make their own food using energy from sunlight. The process take place in two steps;light depedent stage (photolysis) and the light indepedent stage (carbon iv fixation), resulting to production of simple sugars and oxygen gas. The simple sugars produced are then stored in form of starch by the plant or used in cellular respiration to produce energy.

That is true tge cactus as a structural adaptation to its envirinment has it leaves reduced to spines. but this doesnt mean it cant produce food it produces food because of the presence of chlorophyll in its stem