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