Echinoderms all have radial symmetry and their bodies are segmented into five equal sections. Each of these segments has identical copies of all internal organs. All echinoderms also have spines, although they are not as obvious on some species, and some starfish have more than five arms, but they are always numbered in multiples of five.
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How is the echinoderm's body structured?
- Marine Life
- Echinoderms