Question

what does the notation rr mean to geneticists?
heterozygous alleles
homozygous alleles
dominant alleles
recessive alleles

Explanation:

In genetics, heterozygous alleles are represented by two different alleles (e.g., Rr), where one is dominant (R) and one is recessive (r). Homozygous alleles have two identical alleles (RR or rr). Dominant alleles are represented by uppercase letters (R), and recessive by lowercase (r), but Rr is a combination of both, so it's heterozygous.

Answer:

A. heterozygous alleles