9781422270660

WORDS TO UNDERSTAND

clean energy: sources of energy—such as solar, wind, water, geothermal, bioenergy, and nuclear—that cause less damage to the environment than fossil fuels (coal, petroleum, natural gas) economist: a worker who collects and studies data, historical trends, and current business inclinations to help businesses and other organizations make decisions regarding financial, production, and other issues doctorate: an educational credential that is awarded to an individual who completes two or three additional years of education after earning a master’s degree; it is also known as a doctoral degree (PhD) infrastructure: in relation to the construction industry, the systems of a city, region, or nation, such as communication, sewage, water, transportation, dams, and electric

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