Biology Question on Photosynthesis in higher plants

Question

Who demonstrated that green plants purify the foul air produced by breathing animals and burning candles?

Answer 1

Solution

Joseph Priestley $(1770)$ observed that a candle burning in a closed space - a bell jar, soon gets extinguished. Similarly, a mouse kept in a closed space would soon get suffocated and die. However, when he placed a mint plant in the same bell jar, he found that the mouse stayed alive and candle continued to burn. Priestley hypothesised that foul air or phlogiston produced during burning of candles or animal (mice) respiration could be converted into pure air or dephlogiston by plants (mint). In $1774$ , Priestley discovered oxygen.