Answer:
If crossed with another heterozygous plant, the majority of progeny will have the dominant flower color.
Step-by-step explanation:
If you cross a dominant heterozygous plant with a single gene with another heterozygous plant, because of the dominance effect in the heterozygous plant, the phenotype is affected and because dominance makes it difficult to distinguish between a homozygous and heterozygous plant, the heterozygous dominant plant in this case will act like a homozygous parent and hence the majority of progeny will have dominant flower color.