Sea Sponges have adapted to their environment underwater by creating holes and canals to allow water to flow through the pores. Sea sponges are also male and female, therefore they are able to reproduce with themselves.
Mollusks not always, but usually have a shell to protect their very fragile bodies. They have also developed new ways to form to the little crevice they are trying to fit into.
Crustaceans have two antennae that they use for sensing and touching. They also have segmented legs for easy walking and manuvering.