purple flowers are dominant over white flowers. a heterozygous purple flower is crossed with another…

Answer:

A. 3:1

Explanation:

Step1: Define alleles

Let P be the dominant allele for purple and p be the recessive allele for white. A heterozygous purple - flower has the genotype Pp.

Step2: Set up Punnett - square

When Pp is crossed with Pp, the possible gametes from each parent are P and p. The Punnett - square has 4 boxes: (P from one parent and P from the other gives PP; P from one and p from the other gives Pp; p from one and P from the other gives Pp; p from one and p from the other gives pp).

Step3: Determine phenotypes

PP and Pp result in purple flowers (dominant phenotype), while pp results in white flowers (recessive phenotype). Out of 4 possible genotypes (1 PP + 2 Pp+ 1 pp), 3 genotypes (PP and 2 Pp) give purple flowers and 1 genotype (pp) gives white flowers. So the ratio of purple to white is 3:1.