snapdragons occur in nature as either green or yellow plants. a green snapdragon is homozygous and has the genotype cc. a yellow snapdragon is heterozygous and has the genotype cc. suppose that a gardener crosses two yellow snapdragons, and one-third of the offspring are green and two-thirds of the offspring are yellow. what type of allele could be responsible for the 2:1 offspring ratio seen when two yellow snapdragons are crossed?