Ans.Removal of Extra Carbon Dioxide
In daytime, the carbon dioxide produced during cellular respiration is utilized in photosynthesis and hence it is not a waste product. At night, it is surplus because there is no utilization of carbon dioxide. It is removed from the tissue cells by diffusion. In leaves and young stems, carbon dioxide escapes out through stomata. In young roots, carbon dioxide diffuses through the general root surface, especially through root hairs.
Removal of Oxygen
Oxygen is produced in mesophyll cells only during daytime, as a by-product of photosynthesis. After its utilization, in cellular respiration, the mesophyll cells remove the extra amount of oxygen through stomata.