What does the notation rr mean to genetics
heterozygous alleles
homozygous alleles
dominant alleles
recessive alleles

The notation Rr represents heterozygous alleles. This is because the alleles are defined as the variants of a given gene and, as the notation has two different alleles it is heterozygous in nature.The two alleles in the notation are R and r.The allele R is the dominant allele and r is the recessive allele. Since the notation shows that both of these alleles are defining the genotype it is a heterozygous condition.