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union –n. an organization of workers formed to support their interests
net-zero –n. a situation in which nothing is gained and nothing is lost
fossil fuel –n. a fuel, such as coal, oil or natural gas, that is formed from dead plants or animals
drill –v. to make a hole in the earth in an effort to find oil or water
refinery –n. a manufacturing center where a raw material is purified and changed
indigenous –adj. naturally coming from a place; native
tunnel –n. a passage underground
