Question

How do the echinoderm illustrate this phenomena

Answer 1

Echinoderm is the common name given to any member of the phylum Echinodermata (from Ancient Greek, ἐχῖνος, echinos – "hedgehog" and δέρμα, derma – "skin")[2] of marine animals. The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as sea stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies".[3] Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone