Each chromosome contains two identical what

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes 

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