In Terrestrial Environments, Fluid-Filled Body Cavities Function as Hydrostatic Skeletons

In terrestrial environments, fluid-filled body cavities function as hydrostatic skeletons and

A) make locomotion possible in smaller soft-bodied animals like snails.
B) are common in animals with protective hard skeletons.
C) are common in animals that move using muscles attached to limbs.
D) are important for movement in humans.
E) are commonly associated with hard skeletons that support muscular limbs.