AP BIOLOGY

Detailed explanation-1: -1. In radishes, the gene that controls color exhibits incomplete dominance. Pure-breeding red radishes crossed with pure-breeding white radishes make purple radishes.

Detailed explanation-2: -Incomplete dominance occurs in the heterozygote, in which the dominant allele does not dominate the recessive allele entirely; rather, an intermediate trait appears in the offspring. Codominance occurs when the alleles do not show any dominant and recessive allele relationship.

Detailed explanation-3: -Incomplete dominance results in heterozygotes with intermediate phenotypes, as in the case of snapdragons when parents with red flowers and white flowers are crossed resulting in heterozygous offspring with pink flowers.

Detailed explanation-4: -So the correct answer to our question about the expected phenotypic ratio of a dihybrid cross between two heterozygous individuals is (A) nine to three to three to one.