Which example illustrates Darwin's main contribution to the theory of evolution? A. An agricultural pest has been exposed to a pesticide that wipes out the entire species. B. In a laboratory, a scientist chooses the most intelligent mice and breeds them to advance the species. C. When exposed to antibiotics, most bacteria in a population die but some survive and live to reproduce. D. In the African savannah, a scientist observes that a wildebeest calf has inherited its coat pattern from its father.