Agroup of caravans containing 20 people were travelling west on the oregon trail and got horribly lost. they stopped in a very remote part of south dakota. this population was isolated for many decades until your team of researchers found them. of the 20 people from the original group, two were carriers (heterozygous) for cystic fibrosis. assuming the frequency of this allele did not change as their population grew, what was the incidence of cystic fibrosis found by your team of researchers?