Answer:
D. Different plants release different amounts of oxygen
Step-by-step explanation:
In his experiments, Priestley observed that candle remains lighted for some time and then is exhausted. This occurred due to the removal of oxygen from the air inside the jar. Oxygen is required to support burning. Placing the mint plant in the jar along with the candle allowed the candle to remain lighted for long since plants produce oxygen gas as a by-product during the process of photosynthesis.
The oxygen gas released by the mint plant supported the burning of the candle. Placing different plant species in the jar allowed the candle to remain lighted for different time periods. This represents the fact that the rate of photosynthesis and hence, the rate of the release of oxygen by various plant species differ. This resulted in the release of different amounts of oxygen by various plant species to support the burning for different periods of time.