Question

A dihybrid cross is created from plants that are heterozygous for both round seeds and yellow seed color. What is the ratio of offspring that have round seeds and yellow seed color?
1:16
3:16
9:16
16:16

Answer 1

9/16

For each trait, heterozygous × heterozygous gives 3/4 chance of the dominant phenotype (round or yellow). Multiplying: 3/4 × 3/4 = 9/16.