What describes incomplete dominance?

• A. Two heterozygous alleles result in a blended phenotype
• B. Dominant allele completely masks recessive
• C. Recessive allele determines phenotype
• D. Genotype equals phenotype

Answer: (D)

Incomplete dominance happens when neither allele is fully dominant, so the heterozygous phenotype sits between the two homozygous phenotypes. A classic example is red and white flowers: the offspring with one red and one white allele show pink flowers, an intermediate look rather than red or white. This differs from complete dominance, where the dominant allele masks the other; it also differs from codominance, where both alleles are expressed distinctly in the phenotype. Saying genotype equals phenotype would miss this intermediate expression, since incomplete dominance specifically involves the heterozygote producing a phenotype that is between the two homozygous forms.