An insecticide kills most of the ants on a plant. Over time, it is determined that the insecticide is not as effective for killing ants. Which statement best explains this observation?
A The ants killed initially by the insecticide were genetically the same as the surviving ants.
B The ants killed initially by the insecticide had thinner cell membranes than the surviving ants.
C The ants that survived were younger than those that died as a result of the insecticide.
D The ants killed by the insecticide and the surviving ants were genetically different.