Which of the following phenotypes represents a homozygous dominant genotype?

A homozygous dominant genotype is characterized by having two identical dominant alleles for a particular gene, which is represented as "GG." This means that both alleles in this genotype express the dominant trait.

In contrast, a heterozygous genotype, such as "Gg," contains one dominant and one recessive allele, while a homozygous recessive genotype, such as "gg," consists of two identical recessive alleles, which express the recessive trait instead. Therefore, when identifying a phenotype that corresponds to a homozygous dominant genotype, "GG" is the only option that fulfills that criterion.

The understanding of dominant and recessive alleles and their expressions is foundational in genetics, allowing for the prediction of phenotypic outcomes based on the underlying genotypes.