4. Some jellyfish have skeletons that are formed by fluid-filled compartments. This fluid resists compression and thus

supports the body structure from deforming. Which term describes these skeletons?

A. Fluid skeletons

B. Hydrostatic skeletons

C. Exoskeleton

D. Endoskeleton

B. Hydrostatic skeletons

Explanation:

Hydrostatic skeletons are found in organisms with soft bodies like earthworms, jellyfishes, some starfishes and the like. It is formed by coelem, a fluid-filled compartment, which supports the organisms' structures and organs with the use of hydrostatic pressure. It protects the body from external pressures. They move through muscle contractions, which changing the shape of the coelem.