Which Feature Characterizes Hydrostatic Skeletons

Multiple Choice

Which feature characterizes hydrostatic skeletons?

A) Found primarily in vertebrates
B) Consist of a fluid-filled body cavity surrounded by a stiff cuticle
C) Require molting when the animal grows
D) Used by clams in locomotion
E) Contraction of one set of muscles causes the fluid-filled body cavity to bulge in the opposite direction.