How do jellyfish move? with a hydroskeleton with an exoskeleton with an endoskeleton with a circular muscle and the water from the environment

, in its simplest and least complex form, is the skeleton of primitive, more advanced, and in some common, modern day organisms.[1] While more advanced organisms can be considered hydrostatic, they are sometimes referred to as hydrostatic for their possession of a hydrostatic organ instead of a hydrostatic skeleton. A hydrostatic organ and a hydrostatic skeleton may have the same capabilities, but they are not the same.[1] Hydrostatic organs are more common in advanced organisms, while hydrostatic skeletons are more common in primitive organisms. As its name suggests, containing hydro meaning "water", being hydrostatic means that the skeleton or organ is fluid-filled.[2]