What are his observations? We can’t answer this without knowing his observations if those are the conclusions. Please provide the rest of the information and I can answer.
The relationship between the ant and the cicada is Parasitism --- One organism benefits, by hurting the other organism. I hope that this is the answer that you were looking for and it has helped you. Have a nice day.
Enzymatic activity will increase as more enzyme is added but will stop once all the substrate has been reacted with as it has nothing to act on