In pea plants, flowers are either white or purple; the purple color is produced by pigments called anthocyanins. the production of anthocyanins is a two-step process: the first is controlled by the c gene and the second by the p gene. the genes are not linked and both must produce functional proteins for anthocyanin to be expressed. for each gene, the dominant (c and p) alleles produce functional proteins. you cross two pea plants, each with the genotype ccpp. what proportion of their offspring will have white flowers?

I should remember that it is important to show uppercase and lower case in genetics, to differenciate the dominant alleles from the recessive ones.

If we cross two ccpp genotypes (all lowercase = all recessive alleles that produce unfunctionnal proteins) we will obtain 100% of white pea plants because all the offspring will have the ccpp genotype (without any dominant allele producing functionnal protein).

the offspring would all be white. if the parents are both white flowers then they have the genotype rr, which when crossed results in an all white punnet square.