Identical alleles for a trait are called

• A. Gene
• B. Allele
• C. Heterozygous
• D. Homozygous

Answer: (D)

Identical alleles for a trait are called homozygous. In a diploid organism, you have two copies of each gene. When those two copies are the same version of the gene—both alleles are the same—you’re homozygous for that trait. This can be two dominant copies or two recessive copies, like TT or tt in a gene with alleles T and t. If the two copies are different (one dominant, one recessive), that’s heterozygous.

Understanding these terms helps distinguish between the basic unit (the gene), a version of that gene (an allele), and how the two copies come together (homozygous vs. heterozygous).