Diane Dodd's experiments using fruit flies demonstrated that A) the evolution of reproductive barriers occurs much too slowly to produce measurable effects in the laboratory.
B) new species can form in a single generation by the production of new reproductive structures.
C) formation of a reproductive barrier between two populations is more likely if they experience and adapt to different environmental conditions.
D) reproductive barriers usually are absolute: Either two populations are fully willing and able to interbreed, or they are strictly separated by a fully effective reproductive barrier.