Question on: JAMB Biology - 2000

The coelom is a fluid-filled body cavity found in many animal groups. * **Coelenterata (also known as Cnidaria):** These animals, such as jellyfish and corals, lack a true coelom. They have a simple sac-like body plan with a single opening that serves as both mouth and anus. The space within the body is called the gastrovascular cavity. * **Mollusca:** Molluscs (e.g., snails, clams) have a coelom, although it is often reduced and surrounds the heart. * **Reptilia:** Reptiles (e.g., snakes, lizards) are advanced animals that possess a coelom. * **Arthropoda:** Arthropods (e.g., insects, spiders) possess a coelom