32. If available, the body will always digest which macromolecule for energy first? A. lipids B. proteins C. enzymes D. carbohydrates

33. The class of macromolecule that would most likely be involved in contracting muscles would be A. lipids B. proteins C. enzymes D. carbohydrates

D, carbohydrates are the body’s main source of energy.

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