The horticulturist crosses two geraniums from the F1 generation. Look at the Punnett square to see this cross.

[tex]\[
\begin{array}{|c|c|c|}
\hline
& R & r \\
\hline
R & RR & Rr \\
\hline
r & Rr & rr \\
\hline
\end{array}
\][/tex]

Which ratio of red-to-white flowering plants would she expect to see in the phenotypes of the F2 generation?

A. 2 red : 2 white
B. 3 red : 1 white
C. All red
D. 1 red : 3 white

To determine the ratio of red-to-white flowering plants in the F2 generation, let's analyze the given Punnett square.

The Punnett square shows how two geraniums with genotypes from the F1 generation are crossed. Here's what each combination represents:

- RR: This results in red flowers.
- Rr: This also results in red flowers, because the dominant allele "R" results in red color.
- rr: This results in white flowers since both alleles are recessive.

Now, let's look at the proportions of each genotype from the Punnett square:

1. RR (Red Flowers): 1 out of 4 squares
2. Rr (Red Flowers): 2 out of 4 squares
3. rr (White Flowers): 1 out of 4 squares

Next, add up the probabilities of the phenotypes:

- Red Flowers = RR + Rr:
- 1/4 (RR) + 2/4 (Rr) = 3/4 of the plants have red flowers.

- White Flowers = rr:
- 1/4 of the plants have white flowers.

Now, let's find the ratio of red to white flowering plants:

- The proportion of red-flowered plants is 3/4, and the proportion of white-flowered plants is 1/4.
- This simplifies to a ratio of 3:1.

Therefore, the horticulturalist would expect to see a 3 red to 1 white ratio in the phenotypes of the F2 generation.