Final answer:
The F2 generation would be all tall with a 1:2:1 phenotypic ratio in flower color due to incomplete dominance. Therefore, there would be a mix of red, pink, and white flowers, all on tall plants. The provided options A, B, C, and D do not accurately reflect this outcome.
Step-by-step explanation:
The F2 phenotypic ratio from a cross of RR dd with rr DD can be predicted using the principles of Mendelian genetics. In this case, RR indicates a homozygous red-flowering plant, while rr indicates a homozygous white-flowering plant. Since the colors red and white follow an incomplete dominance pattern, the F1 generation would all be pink (Rr).
For the tallness trait, D is dominant and indicates tall plants, while d is recessive and indicates dwarf plants. The cross with dd and DD parents would result in F1 offspring all being heterozygous (Dd) and thus tall.
In the F2 generation, when considering the independent assortment of the two traits, the colors would segregate following a 1:2:1 ratio (red:pink:white), while tallness would be consistent across all offspring due to the presence of at least one dominant D allele. Consequently, the F2 generation from this cross would be all tall and follow a phenotypic color ratio of red, pink, and white, indicating that none of the answers A, B, C, or D is correct because they do not account for the incomplete dominance in flower color.