Question

Why do plants produce carbon dioxide as a waste product during night time

Answer 1

Respiration is the process of conversion of food into energy. In this process, CO2 is formed and O2 is used.

Photosynthesis is the process of formation of food by absorbing CO2 and releasing O2 as byproducts in plants.

During day time, plants perform photosynthesis (since sunlight is present). Thus, plants use their own CO2 released by respiration process.

Thus during day time, plants give out more of O2 compared to CO2.

But during night time, plants perform only respiration and no photosynthesis (since absence of sunlight). Thus concentration of CO2 released is higher during night time.