Which genotype represents a homozygous dominant arrangement for a single trait?

Which genotype represents a homozygous dominant arrangement for a single trait?

• A. Bb
• B. AB
• C. BB
• D. AA

Answer: (C)

Homozygous dominant means having two copies of the dominant allele. For this trait, the dominant allele is B, so two B alleles on both chromosomes give the genotype BB. That makes it homozygous for the dominant allele. A genotype like Bb has one dominant and one recessive allele, so it is not homozygous. The other options don’t fit the allele set for this trait—AB would require two different alleles that aren’t the same gene’s pair, and AA would be two copies of allele A, which isn’t the allele involved here. So BB is the correct representation of homozygous dominant for this trait.

Homozygous dominant means having two copies of the dominant allele. For this trait, the dominant allele is B, so two B alleles on both chromosomes give the genotype BB. That makes it homozygous for the dominant allele. A genotype like Bb has one dominant and one recessive allele, so it is not homozygous. The other options don’t fit the allele set for this trait—AB would require two different alleles that aren’t the same gene’s pair, and AA would be two copies of allele A, which isn’t the allele involved here. So BB is the correct representation of homozygous dominant for this trait.