Answer:
During the day plants produce oxygen by splitting water molecules in the light-dependent reactions of photosynthesis. At the same time plants use cellular respiration to produce some of the carbon dioxide needed by the light-independent reactions to make sugars. During the night plants produce carbon dioxide because cellular respiration takes place
Step-by-step explanation:
Photosynthesis is the manufacture of organic food materials in presence of sunlight energy while respiration is the breakdown of food materials in the presence of oxygen. Photosynthesis produces oxygen as a by-product that is used in respiration. Respiration produces carbon dioxide that is used in photosynthesis.