How is oxygen added to the air? a)plants release oxygen as a waste product of photosynthesis. b)animals release oxygen as a waste product of respiration. c)oxygen is released from the burning of fossil fuels, such as coal. d)oxygen is released by plants as a waste produce of respiration.

The correct answer would be b

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature