According to paragraph 4, which of the following statements is true about the energy expended by animals in walking? A. It requires more energy for a walking animal to overcome the friction in its joints and muscles than to support its body weight. B. The process involved in walking that usually requires the most energy is producing accelerations and decelerations. C. Whether or not walking requires more energy than other types of locomotion depends on the anatomy of a given animal. D. The energy generated by momentum during walking is greater than the amount of energy expended in accelerating and decelerating.