Worms move using an hydrostatic skeleton. how do worms move?
a. their bones are filled with water, which provides weight for the skeleton.
b. the change in body structure is caused by contraction of muscles compressing the watery fluid
c. the muscles contain vacuoles, which when filled, provide a rigid internal structure.
d. the term hydrostatic skeleton simply refers to moist environment. they generate movement just as arthropods do.

The correct answer is B. Worms move through changes in body structure caused by contraction of muscles compressing their watery fluid.

Explanation:

The hydroskeleton consists of a fluid-filled cavity, surrounded by muscles. The fluid pressure and the action of the muscles that border it, serve to change the body's shape and produce a movement such as digging or swimming. The successive contraction of various metamers, which are provided with bundles of circular and longitudinal muscle fibers, stretching and thickening parts of the body, allow it to move horizontally. Hydrostatic skeletons have a role in the locomotion of annelids, nematodes and other invertebrates. The hydroskeleton has similarities with the hydrostatic muscles.

not: both offer magnification to the atomic level.