Answer:
Increasing the substrate concentration.
Explanation:
Increasing the substrate concentration can increase the rate of the reaction to a certain point. However, once all of the enzymes bounded to the substrate, any further addition of it will not be going to affect or increase the rate of the reaction at all, as all the enzymes will be saturated and working in their maximum rates.
It would be .5. If there is a probability that two thing could happen it would be 50 50 shot.
