A situation where a single individual expresses two different alleles is referred to as:

• A. codominance
• B. epistasis
• C. complete dominance
• D. incomplete dominance

Answer: (A)

Verified step by step guidance

1. Understand the definitions of the key terms: codominance, epistasis, complete dominance, and incomplete dominance.
2. Codominance occurs when both alleles in a heterozygous individual are fully expressed, resulting in a phenotype that shows both traits simultaneously.
3. Epistasis refers to a situation where one gene affects or masks the expression of another gene, not the expression of two alleles in the same gene.
4. Complete dominance means one allele completely masks the effect of the other allele in a heterozygote, so only one trait is visible.
5. Incomplete dominance results in a blended phenotype where neither allele is completely dominant, producing an intermediate trait.