a geneticist isolates two mutations in a bacteriophage. one mutation causes clear plaques (c) and the other produces minute plaques (m). previous mapping experiments have established that the genes responsible for these two mutations are 12 map units apart. the geneticist mixes plaques with genotype c m- and genotype c- m and uses the mixture to infect bacterial cells. she collects the progeny phages and cultures a sample of them on plated bacteria. a total of 500 plaques are observed. what numbers of the different types of plaques (c m , c-m-, c m-, c-m ) should she expect to see? g