(a) Water: Water (H2O) undergo photosynthesis in light reaction.
H2O → 2H+ + O + 2e–
O + O → O2 ↑
As a result ATP and NADPH are formed which are used in formation of carbohydrates from CO2.
Water also releases O2 which is given out during photosynthesis.
(b) Chlorophyll: It traps solar (light) energy and utilises it in fixing oxides of carbon (CO2) and hydrogen (H2O) as carbohydrates.
(c) Stomata: They help in exchange of gases. Carbon dioxide needed in photosynthesis is taken in through stomata. Oxygen produced in photosynthesis is given out through stomata.