Sea stars, sometimes known as a starfish, are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" are sometimes differentiated, with "starfish" used in a broader sense to include the closely related brittle stars, which make up the class Ophiuroidea, as well as excluding sea stars which do not have five arms (have Many arms), such as the sun stars and cushion stars.

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