With one gene controlling a trait we have three possible genotypes, AA, Aa and aa and depending on the allelic interactions (dominance or incomplete dominance) we can have two or three phenotypes. As more and more genes control a trait, a greater number of genotypes are possible. The formula that predicts the number of genotypes from the number of genes is 3 to the power n. (n is the number of genes.) The following is the number of genotypes for a selected number (n) of genes which control an arbitrary trait.
Coal-Powered Electric Cars Out-Pollute Fossil Fuels. by. If the energy used to power electric vehicles comes from traditional resources such as burning coal rather than renewable sources, driving battery-powered cars will pollute the air more than cars powered by fossil fuels.
Charging up a Detroit Electric car, 1919. At the turn of the last century, electric cars were more desirable than vehicles powered by steam or gas. In the 1920s, the gasoline internal combustion automobile became dominant. An electric car is powered by an electric motor instead of a gasoline engine. The electric motor gets energy from a controller, which regulates the amount of powerâbased on the driverâs use of an accelerator pedal.