The reactants needed for photosynthesis are carbon dioxide and water; these are obtained through a combination of pores on leaves and root systems in the ground.
Carbon dioxide enters through tiny holes in a plant's leaves, flowers, branches, stems, and roots. Plants also require water to make their food. ... The energy from light causes a chemical reaction that breaks down the molecules of carbon dioxide and water and reorganizes them to make the sugar (glucose) and oxygen gas.
