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displaced - v. to force (people or animals) to leave the area where they live
tendency - n. a quality that makes something likely to happen or that makes someone likely to think or behave in a particular way
external - adj. located, seen, or used on the outside or surface of something
mud - n. soft, wet dirt
impact - n. a powerful or major influence or effect
vulnerability - n. easily hurt or harmed physically, mentally, or emotionally
tributaries - n. a stream that flows into a larger stream or river or into a lake
