What is the role of air in the growth of green plants ?

Explanation

1) Joseph Priestly in 1770 performed a series of experiments that revealed the essential role of air in the growth of green plants.
2) Priestly discovered oxygen in 1774.
3) Priestly observed that a candle burning in a closed space, a bell jat, soon gets extinguished.
4) Similarly, a mouse would soon suffocate in a closed space of the bell jar.
5) He concluded that a burning candle or an animal, both somehow, damage air.
6) But when he placed a mint plant in the same bell jurs, he found that the mouse stayed alive and the candle when lighted from outside continued burning in the presence of the mint plant.
7) Priestly assumed as plants restore to the air whatever breathing animals and burning candles remove.