Question

Why would it not be appropriate to use VO₂ to calculate Q10 if cockroaches were endothermic homeotherms?

Metabolism would be relatively constant across the range of temperatures and Q10 would be zero.

Body temperature would be relatively constant, so changes in VO2 would indicate thermoregulation, not the effect of temperature on metabolism.

Q10 would not be relevant when the organism is in its thermal neutral zone (TNZ), but it would be relevant outside of the TNZ when metabolism is affect by temperature.

Answer 1

Option 2nd is the correct answer. Q10 is the factor which represents the rate of a reaction increases when temperature rises by 10 degree. VO2 indicates oxygen uptake. A change in metabolic rate change the VO2. Although cockroaches are ectothermic  and their body temperature changes with the change in environmental temperature, under endothermic homeotherms condition the body temperature is constant as endotherms generate heat according to need and thus, they maintain their body temperature constant. Thus, under endothermic condition the body temperature will be relatively constant and hence there will be no change in metabolic reaction and thus changes in VO2 would indicate thermoregulation.