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A coal scraper machine works on a pile of coal at American Electric Power's Mountaineer coal power plant in 2009 in New Haven, W. Va. The state, in which coal mining is a major industry, is one party planning to sue the Environmental Protection Agency regarding new power plant regulations announced on Monday. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

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Yaupon growing in the wild in east Texas. This evergreen holly was once valuable to Native American tribes in the southeastern U.S., which made a brew from its caffeinated leaves. Murray Carpenter for NPR hide caption

itoggle caption Murray Carpenter for NPR