Organelles, such as mitochondria
Answer:
Its A ive done it before if you need proof here http://assessment.aaas.org/items/CE056001#/0
Explanation:
PH – depends on the environment the cell that is respiring is in.
Temperature; as it increases, the rate increases…to a point (too hot and enzymes denature!)
I am not that good, but maybe the digestive system