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shellfish –n. an animal, such as a crab or oyster, that has a hard outer shell and that lives in the water
species –n. a group of animals or plants that are similar and can produce young animals or plants
parasite –n. an animal or plant that lives in or on another animal or plant that gets food and protection from it
digestive –adj. related to the process by which food is changed into a simpler form after it is eaten
stage –n. a particular point or period in the development of something
benefit –n. a good or helpful effect
