They began to discuss about photosynthesis. Kenneth had good knowledge about photosynthesis so he went on to explain that plants release oxygen during the process of photosynthesis. Plants, like animals use oxygen for respiration.
Meanwhile John was curious that, why all the oxygen of atmosphere does not get used up ?Choose the correct explanation for John's question.
Plants, during the process of photosynthesis consume carbon-dioxide present in air and produce oxygen along with their food. Plants also consume oxygen during respiration but the amount of oxygen produced during photosynthesis is more than what they consume during respiration. So plants give out oxygen to the atmosphere which is consumed by animals. Animals release carbon dioxide. So there is a balance of oxygen and carbon dioxide in the atmosphere is maintained by plants and animals.