Red-flowering snapdragons are homozygous for the R1 allele, while white-flowering snapdragons are homozygous for the R2 allele. Heterozygous plants (R1R2) have pink flowers. What phenotypes and their respective probabilities can be expected among the F1 offspring from the following crosses?

To determine the expected phenotypes and their respective probabilities among the F1 offspring from a cross between red-flowering snapdragons (homozygous R1R1) and white-flowering snapdragons (homozygous R2R2), we must look at the genotypes of the parents and use a Punnett square to predict the offspring's genotypes and phenotypes.

Cross 1: Red (R1R1) x White (R2R2) Parental Genotypes: - Red-flowering snapdragons: R1R1 - White-flowering snapdragons: R2R2

Since red-flowering snapdragons are homozygous for the R1 allele and white-flowering snapdragons are homozygous for the R2 allele, all the offspring (F1 generation) will be heterozygous (R1R2).

Punnett Square:

R2 | R2 ------------- R1 | R1R2 | R1R2 R1 | R1R2 | R1R2

All of the F1 offspring will have the genotype R1R2 and, according to the information provided, these heterozygous plants have pink flowers.

Phenotypes and Probabilities among the F1 Offspring: - Pink flowers: 100% (1.0)

Thus, each F1 offspring from the cross of a red (R1R1) and a white (R2R2) snapdragon will have pink flowers, which is the intermediate phenotype due to incomplete dominance.