The three events that occur during the process of photosynthesis are:
(i) Absorption of light energy by chlorophyll.
(ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
(iii) Reduction of carbon dioxide to carbohydrates.
Role of stomata These help in the gaseous exchange between the plant and its atmosphere. Thus, it assist in supply of carbon dioxide, essential for photosynthesis.