What term describes an organism that has two identical alleles at a locus?

The correct term for an organism that has two identical alleles at a locus is "homozygote." In genetics, an allele refers to one of the different forms of a gene that can exist at a specific locus on a chromosome. When an organism possesses two copies of the same allele for a particular gene—such as both being dominant or both being recessive—it is classified as a homozygote.

This is important in genetics because homozygosity can affect how traits are expressed in the phenotype, which is the observable characteristic or trait of an organism. However, phenotype itself does not describe the genetic makeup but rather the physical manifestation of that makeup.

On the other hand, the term "locus" refers to the specific location or position of a gene on a chromosome, and "allele" refers to the variations of the gene that can exist at that locus. Thus, while these terms relate to genetics, they do not pertain directly to the condition of having identical alleles.