Which principle states that some alleles are dominant and others are recessive?

• A. Principle of Segregation
• B. Principle of Dominance
• C. Law of Independent Assortment
• D. Central Dogma

Answer: (B)

Dominance is the concept being tested: in a heterozygous individual, the dominant allele masks the effect of the recessive one, so the trait associated with the dominant allele appears. If you have one dominant and one recessive allele, you express the dominant phenotype; you only see the recessive phenotype when two recessive alleles are present. For example, tall (dominant) vs short (recessive) in peas: tall can be produced by TT or Tt, while short appears only in tt. This idea is separate from how alleles segregate during gamete formation or how genes assort independently, and from the central dogma about the flow of genetic information. Hence, the principle describing dominance is the correct one.