The hardy-weinberg principle states that in a population do not change unless outside factors affect the gene pool.

Answer;

-Allele frequencies

The hardy-weinberg principle states that allele frequencies in a population do not change unless outside factors affect the gene pool.

Explanation;

Hardy-Weinberg principle  is a mathematical model that describes how genotype frequencies are established in sexually reproducing organisms.

The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. The Hardy-Weinberg equilibrium can be disturbed by a number of forces, including mutations, natural selection, nonrandom mating, genetic drift, and gene flow.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.