Red flowered snapdragons are crossed with white flowered, producing all pink snapdragons in the F1. What would you expect if you crossed white with white?

The cross described above is an example of a monohybrid cross involving a single gene coding for flower colour in snapdragon plants. According to the question, one allele codes for red flower, while the other for white flower.

When both red and white flowered plants were crossed, an all pink-flowered plants resulted in the F1 generation. This is due to INCOMPLETE DOMINANCE, which is a genetic scenario whereby an allele does not completely mask the expression of another in an heterozygous state, instead they form a third phenotype that is intermediate to both parental phenotypes.

But in the case of crossing two white-flowered snapdragons, all the F1 offsprings will be white-flowered because the parents are homozygous i.e. contains the same alleles.

For example, RR (red flower) is crossed with rr (white), to produce an heterozygous/hybrid Rr (pink).

Hence if rr (white) and rr (white) crosses, all rr (white) offsprings will result.