Jeanine is 55. according to her doctor, jeanine's reproductive capacity has ended. she has reached the midlife reproductive transition called

It is called pre menopausal stage or menopause in which causes night sweats, hot-cold spells and irrational mood swings...

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