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The document summarizes digestion, excretion, and respiration in various invertebrate groups. It describes the digestive systems of mollusks, annelids, arthropods including crustaceans, chelicerates, and uniramians, and echinoderms. It notes they have a mouth, esophagus, one or more stomach chambers, an intestine, and anus. It also describes their excretory structures like nephridia, green glands, Malpighian tubules, and coxal glands. Finally, it outlines their respiratory organs such as gills, lungs, book lungs, spiracles, and trachea depending on if they are aquatic or terrestrial.