27) Electric vehicles often have been proposed as an environmentally sound alternative to the gasoline engine for transportation. In response to state initiatives, several car manufacturers now include electric vehicles among their available models. In spite of these state initiatives, the penetration of electric vehicles into the transportation sector of the United States, as well as other countries, remains modest. (a) Identify and describe two environmental benefits to using electric vehicles in place of gasoline-powered engines for transportation. (b) Estimate the potential reduction in petroleum consumption (in gallons of gasoline per year) that could be achieved in the United States by introducing electric vehicles under the following assumptions: 1. The mileage rate for the average car is 25 miles per gallon of gasoline. 2. The average car is driven 10,000 miles per year. 3. The United States has 150 million cars. 4. 10 percent of United States cars could be replaced with electric vehicles. (c) Some people have suggested that electric vehicles only shift the emission of air pollutants from dispersed sources to point sources. Explain and defend or refute this statement. (d) Propose two potential new United States government policies that would encourage the widespread use of electric vehicles. Explain.