Question

practice identifying dominant and recessive alleles
a homozygous genotype can show either a dominant or a recessive trait, because both of the alleles are the same
an example of a homozygous dominant genotype is
an example of a homozygous recessive genotype is
(need a refresher? watch this video on heterozygous and homozygous)

Explanation:

To determine the dominant genotype, we recall that a dominant genotype can be homozygous dominant (both alleles dominant) or heterozygous (one dominant, one recessive), but the question specifies homozygous dominant. Among the options (AA, Aa, aa), AA has two dominant alleles (assuming 'A' is dominant), so it's the homozygous dominant genotype. For the homozygous recessive, we need two recessive alleles, so 'aa' (since 'a' is recessive here). The reason a homozygous genotype shows a trait is because both alleles are the same (so same allele expression).

Answer:

Dominant genotype (homozygous): AA
Homozygous recessive genotype: aa
Reason for homozygous trait expression: the same (both alleles are the same)