DDT is a synthetic compound commonly used as an insecticide. It was used to control mosquito species that commonly spread diseases like malaria. The data show the percent resistance for three species of mosquitoes over three decades. What explains the trend seen in the data? A) Genetic drift resulted in the random deaths of non-resistant insects, leaving only resistant mosquitoes to breed. B) Artificial selection favored genotypes that were bred by humans to maintain the desired traits in the mosquito populations. C) Gene flow between the three species increased the genetic diversity of the populations, resulting in more DDT-resistant species over time. D) Natural selection favored resistant members of the species, which survived and reproduced at a greater frequency than non-resistant mosquitoes.
he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?
a = executive branch; b = judicial branch