Answer:
Sunlight.
Explanation:
Sunlight is responsible for proper functioning of stomata present on the leaves because the stomata only opens when there is sunlight and when the stomata opens, carbondioxide gas is absorbed by the leaves from the air while the water is taken from the roots which combines together to form glucose and oxygen. Glucose is stored in different parts of the plant while some oxygen is used by the plants in the process of respiration while the remaining oxygen is released in the atmosphere through stomata.