a) A. Stabilization selection - It is seen when extreme phenotypes on both ends of the spectrum are unfavourable resulting in the reproductive success of those near the mean. B. Directional selection- It is the condition in which organisms at one extreme corner in the range of phenotypes are favoured over the other organisms in the range. C. Disruptive selection- It is the condition in which organisms at both extremes in a range of phenotypes are favored over the ones present in the middle of the range. b) Hardy–Weinberg principle states that allele and gene frequencies in a population will remain constant from one generation to the next if certain conditions are kept constant. These conditions are-  1) Population is large 2) Random mating 3) Absence of mutation