ess areas of Northern Alaska.
             Most of the energy consumed is ultimately generated by the combustion of fossil fuels, such as coal, petroleum, and natural gas. The world has only a finite supply of these fuels, which are in danger of being used up. Also the combustion of these fuels releases various pollutants, such as monoxide and sulfur dioxide, which pose health risks and may contribute to acid rain and global warming. Environmentalists have become increasingly alarmed in the latter half of the 20th century at the widespread destruction imposed on sensitive wild lands during the exploration. Some examples of these wild lands are the tropical rainforests, the arctic tundra, and coastal marshes.
             Hydroelectric power is an important source of energy. Hydroelectric power or water power is a mechanical energy derived from falling or flowing water, such as rivers, streams, and the overflow of dams. Water flowing from a higher level to a lower level (a dam or waterfall) is used to activate a turbine that driv
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