AP BIOLOGY

Detailed explanation-1: -The round seeds are dominant and wrinkled seeds are recessive. Thus, in the first filial generation (F1), when the homozygous round (RR) is crossed with homozygous wrinkled (rr), then the resulting offspring is produced with a genotype Rr which is heterozygous dominant genotype.

Detailed explanation-2: -So, the correct option is ‘303 rounded: 301 wrinkled’.

Detailed explanation-3: -In pea plant, round seed is a dominant trait while wrinkled seed is a recessive trait. Here, ‘R’ is the dominant allele and ‘r’ is the recessive allele for the seed shape of the pea plant. The plant with round seeds would have genotype RR. Then, the plant with genotype rr would have wrinkled seeds.

Detailed explanation-4: -Based on this observation round seeds is the dominant phenotype. With dominant being round seeds that would mean wrinkle seeds are the recessive trait. Therefore a cross of heterozygous for round with a homozygous recessive for wrinkled, will yield an F1 generation that has 50% round seeds and 50% wrinkle seeds.