What is incomplete dominance?

• A. Heterozygotes show an intermediate phenotype that is a blend of both alleles.
• B. One allele masks the other completely.
• C. Both alleles are expressed fully and simultaneously.
• D. A phenotype shows only recessive trait.

Answer: (A)

Incomplete dominance happens when neither allele is fully dominant, so a heterozygous individual shows a phenotype that sits between the two parental traits. For example, crossing red and white flowers can yield pink offspring, because the red and white alleles blend rather than one completely masking the other. The other patterns describe different inheritance: one allele fully masks the other (complete dominance), both alleles are expressed fully and at the same time (codominance), or a recessive trait appears at all (recessive phenotype). So the best description of incomplete dominance is the intermediate phenotype in heterozygotes.