Question

What does the notation Rr mean to geneticists

Answer 1

it means really dumb rabbits

NAH JK

Homozygous: two of the same allele. Rr is therefore Heterozygous

Answer 2

R is a dominant recessive trait while the little r is non-dominant.
for example, brown eyes are dominant over blue eyes, so the brown eyes would win over the non dominant trait.