Answer:
They have a star-like appearance and are spherical or elongated. They are exclusively marine animals. The organisms are spiny-skinned. They exhibit organ level of organization.
Summary
Echinoderms show radial symmetry and have an endoskeleton and a unique water vascular system. Some have spines.
Echinoderms generally reproduce by external fertilization; regeneration is fairly common among echinoderms.
Explanation:
Hope it helps
