Answer:
Joseph Priestly observed that a candle alone in a jar did not stay lit for long.
Priestly observed that adding a plant to the jar caused the candle to stay lit longer.
Priestly inferred that plants give off oxygen during photosynthesis, providing the oxygen needed for the candle to burn.
Priestly inferred that the burning candle gave off carbon dioxide, which was used by the plant.
Step-by-step explanation: