The genotype needed for a nose to be considered small is homozygous recessive, represented as aa.
In this case, the allele for a small nose is recessive, while the alleles responsible for larger nose sizes exhibit incomplete dominance. This means that if a person has two copies of the recessive allele (aa), they will express the small nose trait. If they have one dominant allele and one recessive allele (Aa), they will have an intermediate nose size, and only those with the aa genotype will have the smallest nose size.