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 shows a phenotypic ratio of 9:3:3:1. This ratio is a result of the independent assortment of alleles for different traits. Each trait (seed color and seed shape) is passed on independently. For example, the inheritance of the allele for seed shape (round or wrinkled) does not influence the inheritance of the allele for seed color (yellow or green). This is in line with Mendel's law of independent assortment.

• The first option about traits being inherited as pairs, sets, or groups is too vague and not specific to the dihybrid cross result.
• The second option about dominant masking recessive is related to monohybrid cross concepts (like 3:1 ratio in monohybrid cross) and not directly to the dihybrid cross ratio shown here.
• The third option about gametes carrying one allele per trait is related to Mendel's law of segregation (which is about a single trait's allele separation during gamete formation) and not the dihybrid cross result.

Answer:

Traits are passed independently of one another.