During which stage of meiosis do homologous chromosome pairs line up in the middle of the cell?

OK so the phase you are looking for will be Metaphase I

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