A.B.C.DList IGene poolGenetic driftGene flowGene frequencyIV.II.III.I.List IITotal number of genes and their allelesWhen change in gene frequency occurs by chanceWhen gene migration/transfer of genes into or outof population occurs multiple times.According to Hardy Weinberg principle, genefrequency remains stable within generations. Hence [A-IV, B-II, C-III, D-I] is the correct match.