Babby was a wild chimpanzee who was highly stressed when placed in the confinement of a zoo. her subsequent difficulty recovering from an infectious disease most likely resulted from

It most likely resulted from a bite from another monkey that was in confinement with Babby. Since the other monkey previously was treated for an infectious disease, it is most likely that monkey passed on the disease when he bit Babby.

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