1. What is the independent variable (x axis) in this experiment? How can you tell (based on the graph)?

Some of her  assignments would be creation of drugs. she is a medical chemist after all so she'd need to have the necessary knowledge to make medicine which can later be sold in a pharmacy 

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