d) Photosynthesis and respiration:

Photosynthesis: process by which green plants and certain other organisms use the energy of light to convert carbon dioxide and water into the simple sugar glucose.An extremely important byproduct of photosynthesis is oxygen, on which most organisms depend.

Respiration: Here we take oxygen and exhale carbon dioxide where as in plants in day time co2 is taken and o2 is given off.



in that answer... respiration and photosythesis both occur in plants together... but resporation become dominant in night due to absence of photosynthesis.... in photosynthesis CO2 is taken and O2 is removed while in respiration always O2 is taken and CO2 is released.