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Unformatted text preview: differences. The phylum Mollusca refers to soft-bodied creatures that possess hard shells of their own secretion. Though mollusks are close relatives to annelids and arthropods, they have a more compact form of body segmentation. The class Gastropoda, which include creatures with expanded, flattened foot, and the class Bivalvia, which include clams, are to be studied for the phylum. The phylum Echinodermata refers to a number of marine animals that are all characterized by a core-with-five-spokes body organization. It includes the class Asteroidea, which includes sea stars, the class Echinoidea, which includes sea urchins, and the class Ophiuroidea, which includes an assortment of suspension feeders. They are to be studied for their unique and individual characteristics....
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- Spring '08