Please Explain

Hi, for a necessary assumption question, we can show an answer is wrong by negating it and seeing if that destroys the argument. We can negate E by saying that the energy needed to run at a given speed is not always proportional to the animals surface area. This does not contradict the argument. The argument is about running uphill, perhaps the relationship is only true of removing uphill, and is not true of running downhill or on level ground.