An organism that has two identical alleles for a trait is called what?

An organism that has two identical alleles for a trait is called what?

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

Answer: (B)

Having two identical alleles for a trait means the organism is homozygous for that gene. This means the two copies of the gene carry the same allele, such as BB or bb. The opposite situation is heterozygous, where the two alleles are different (like Bb). An allele is one version of a gene, while the genotype is the pair of alleles an organism has for that gene—whether they are the same (homozygous) or different (heterozygous).

Having two identical alleles for a trait means the organism is homozygous for that gene. This means the two copies of the gene carry the same allele, such as BB or bb. The opposite situation is heterozygous, where the two alleles are different (like Bb). An allele is one version of a gene, while the genotype is the pair of alleles an organism has for that gene—whether they are the same (homozygous) or different (heterozygous).