what does the notation rr mean to geneticists?\nheterozygous alleles\nhomozygous alleles\ndominant…

Brief Explanations:

In genetics, when an organism has two different alleles for a gene (one dominant - represented by a capital letter and one recessive - represented by a lowercase letter), it is heterozygous. Here, R is a dominant allele and r is a recessive allele, so Rr represents heterozygous alleles.

Answer:

heterozygous alleles