I had it down to A and D and chose D. With that said, can someone destroy my reasoning for why A is not the right answer so that this sticks...
Ok, so what if pollen is transported from one region to another by wind, and human movement, we would have to assume that the pollen transferred is indistinguishable from the pollen that is KNOWN to have been unique to that area.
http://7sage.com/lsat_explanations/lsat-49-section-4-question-08/
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