In the laboratory, fruit flies (Drosophila) were artificially selected for the number of bristles on their bodies. One population (R) was selected for low numbers of bristles, a second population (S) for high numbers of bristles.
After 35 generations (about 1 year's time), the two populations R and S were studied. Researchers found
A. a huge increase in S, a huge decrease in R, with no overlap whatsoever.
B. no change was seen; it's much too soon.
C. a vast, overlapping range of bristle numbers was seen.
D. a slight increase in bristles in S, a slight decrease in R, with a little overlap in the middle ranges.
E. some slight increase of bristle numbers was already evident.
Answer: A
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