Question

gregor mendel used pea plants that were heterozygous for each of two traits—seed color and seed shape—to generate a dihybrid cross. the phenotypic ratio of the resulting offspring was nine with round and yellow seeds, three with round and green seeds, three with wrinkled and yellow seeds, and one with wrinkled and green seeds. from these results, what could mendel conclude? traits are inherited as pairs, sets, or groups. traits that are dominant mask traits that are recessive. gametes carry one allele for each trait. traits are passed independently of one another.

Explanation:

Mendel's dihybrid cross (with a phenotypic ratio of 9:3:3:1) demonstrated the principle of independent assortment. This principle means that the inheritance of one trait (e.g., seed color) does not influence the inheritance of another trait (e.g., seed shape). Traits are passed independently of one another.

• The first option ("Traits are inherited as pairs, sets, or groups") is incorrect. Mendel's work showed independent assortment, not inheritance as fixed groups.
• The second option ("Traits that are dominant mask traits that are recessive") is related to Mendel's law of dominance (seen in monohybrid crosses), not the dihybrid cross result (9:3:3:1) which is about independent assortment.
• The third option ("Gametes carry one allele for each trait") is related to the law of segregation (each gamete gets one allele for a trait), not the independent assortment shown in the dihybrid cross.

Answer:

Traits are passed independently of one another.