Correct Response: B. The use of lightweight plastic materials for automobile parts reduces the overall weight of a vehicle. Less overall weight leads to an increase in fuel efficiency which reduces the amount of carbon dioxide emitted into the atmosphere. A is incorrect because the metal parts that would be replaced by the carbon-reinforced plastic parts would most likely be made of steel and are not considered toxic heavy metals. C is incorrect because the combustion of fossil fuels is not directly related to the eutrophication of waterways, which occurs as a result of increased concentrations of nitrogen and phosphorus in water. D is incorrect because ozone depletion is affected by the presence of chlorofluorocarbons in the atmosphere, not by the products of fossil fuel combustion.