Final answer:
A heterozygous pea plant with genotype Yy will produce gametes containing either the dominant Y allele or the recessive y allele, yielding two types of gametes (Y or y). A 2 × 2 Punnett square illustrates the segregation of alleles into gametes, resulting in a 3:1 phenotypic ratio of yellow to green seeds in the offspring.The correct answer is: B. Y or y.
Step-by-step explanation:
If a pea plant is heterozygous for yellow seeds (Yy), the gametes it will produce are either Y or y. This is because heterozygous organisms have two different alleles for a gene, and during gamete formation (meiosis), these alleles are segregated so that each gamete carries only one allele for each gene.
A self-cross of a Yy plant can be represented with a 2 × 2 Punnett square, showing that the plant can produce gametes with either the dominant Y allele or the recessive y allele. As a result, the possible combinations for offspring resulting from a cross of two Yy plants would include YY, Yy, and yy. Among these, YY and Yy genotypes will exhibit the yellow seed phenotype, while yy will exhibit the green seed phenotype. According to Mendel's principle of segregation, each gamete combination is equally likely, which leads to a phenotypic ratio of 3 yellow to 1 green in offspring, as observed by Mendel in his classic experiments.