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The amount of energy required for movement depends on the type of locomotion. A. Swimming is cheaper than flying for animals that swim completely submerged but not for animals that swim on the surface of the water. B. The demands of creating lift and overcoming drag make flying a more costly form of locomotion than swimming. C. The costs of lift and drag are greater for walking and running than they are for swimming. D. For animals that are well adapted to underwater swimming, locomotion requires very little energy because they do not have to support their own body weight. E. Running and walking require more energy than other types of locomotion mainly because of the amount of muscular effort involved in constantly slowing the body down and speeding it up. F. Riding a bicycle at a fast pace requires much less energy than either running or walking.