Porifera's are sponges. Yes, they are animals! They live mostly in the ocean, but you can fond them in freshwater rivers and lakes. Adult sponges are attached to hard surfaces. Water currents carry food and oxygen to them and take away their waste.
All worms have long, narrow bodies with no legs, have tissue, organs, and body systems. Worms are the simplest organisms with a brain. Their brain is a knot of nerve tissue located in its head end. Because of this the worm can detect objects, food, mates and predators.
Invertebrates that have an external skeleton that they molt as they grow. They have segmented body. Jointed attachments called appendages (wings, mouthparts and legs.)
Echinoderms have internal skeleton made of hardened plates making a bumpy texture. System of tubes that are filled with fluid-water vascular system. Tube feet are sticky and can act like suction cups to help with movement. Echinoderms are either male or female, but have external fertilization.
Cnidarians have tentacles with stinging cells used to protect themselves and gather food. Central body cavity. Their bodies have radial symmetry (Symmetrical around a central points)
Mollusks soft bodies, commonly have 1 or 2 shells, but there are some that do not have one. They have thin layer of tissue called the "foot" is used for movement. They also have, bilateral symmetry (same on both sides.) Mollusks that live under water have gills.