Mendel crossed two plants that were heterozygous for purple flower color. which genotypes could he have used to represent the cross? . a. pp pp b. pp pp c. pp pp d. pp pp

The answer is B. Pp Pp.

Imagine that a purple flower color is determined by only one gene on a chromosome. And that gene has two forms (alleles) - one dominant (P) and one recessive (p). Since somatic cells are diploid, which means they have chromosomes in duplicate, in those cells, there will be present two genes with different combinations of forms in genotype.
Therefore, we have 3 combinations of genotypes:
PP - dominant homozygote which has two dominant forms P
pp - recessive homozygote which has two recessive forms p
Pp - heterozygote which has one dominant form P and one recessive form p.

Since Mendel crossed two plants that were heterozygous for purple flower color, that means he chose two plants with Pp genotypes.