24) Which factor controls the breathing rate in mammals? a. Breathing rate is controlled by rate of muscle movement b. Drop of partial pressure of oxygen in blood c. Increase of partial pressure of carbon dioxide in blood 29) Felines (lions, cheetahs, domestic cats) are ambush predators with tremendous speed and agility. The muscle type needed for this characteristic comes at the expense of stamina. This is an example of __. a. adaptation b. a fitness trade of c. negative feedback mechanisms d. acclimation .