Since the United States 0 is trying to combat global warming and reduce its dependence 21() fossil fuels, the United States is committed to identifying alternative sources of energy. Several attractive options have presented 22() in the past few years. In 23() of the fact that there's still no clear frontrunner, "clean" sources 24() solar geothermal and wind power are still some of the most attractive options. Natural gas has also been suggested as an alternative, but the environmental impact of extracting the gas is still unciear Those 25() advocate reduced consumption of disposable goods are also gaining influence Americans consume close to 70 bilion water bottles per year, which has 26() in a serious waste disposal problem It also threatens supplies of underground water that are needed 27()the purposes of drinking and irigating crops