Sponges possess an internal skeleton called what?
exoskelton
hydrostatic skeleton
fluid skeleton
endoskeleton
Sponges have an internal skeleton that gives them support and protection. An internal skeleton is called an endoskeleton . A sponge endoskeleton consists of short, sharp rods called spicules (see Figure below ). Spicules are made of silica, calcium carbonate, or spongin, a tough protein. They grow from specialized cells in the body of the sponge.