Question

during day plant release oxygen instead of carbon dioxide.why?

Answer 1

Cuz it performs photosynthesis. Check out the image for ans.

Answer 2

During the day time, the presence of sunlight helps the plant to prepare its food. This is known as Photosynthesis. The plant takes Co2 from the atmosphere and O2 is given out by the plant in the atmosphere but during night time rate of respiration is more than the rate of photosynthesis and O2 is given in the night time