Question

Sol.(d) [Key Concept: Dihybrid Cross — 9:3:3:1 Independent Assortment] The 9:3:3:1 phenotypic ratio in F2 of a dihybrid cross demonstrates that THE ALLELES OF TWO GENES ARE SEGREGATING INDEPENDENTLY (Mendel's Law of Independent Assortment). This ratio only arises when the two gene pairs assort independently during gamete formation, producing 4 gamete types in equal proportions (1/4 each). If genes were linked, the ratio would deviate from 9:3:3:1 toward higher parental type frequencies.