A plant population has the following distribution of genotypes for flower color.

\begin{tabular}{|c|c|c|c|}
\hline
Genotype & [tex]$RR$[/tex] & [tex]$Rr$[/tex] & [tex]$rr$[/tex] \\
\hline
\begin{tabular}{c}
Number of \\
Individuals
\end{tabular} & 20 & 50 & 30 \\
\hline
Phenotype & Dark red & Red & White \\
\hline
\end{tabular}

What is the frequency of the [tex]$rr$[/tex] genotype?

A. 0.5
B. 1.0
C. 0.2
D. 0.3



Answer :

Sure, let's find the frequency of the `rr` genotype in this plant population step-by-step.

1. Count the Total Number of Individuals:
The number of individuals for each genotype is as follows:
- RR: 20 individuals
- Rr: 50 individuals
- rr: 30 individuals

To find the total number of individuals, we sum these up:
[tex]\[ \text{Total individuals} = 20 + 50 + 30 = 100 \][/tex]

2. Calculate the Frequency of the rr Genotype:
The frequency of a genotype is the number of individuals of that genotype divided by the total number of individuals.
[tex]\[ \text{Frequency of } rr = \frac{\text{Number of rr individuals}}{\text{Total number of individuals}} = \frac{30}{100} = 0.3 \][/tex]

3. Determine the Closest Answer Choice:
Comparing our calculated frequency to the provided choices:
- A. 0.5
- B. 1.0
- C. 0.2
- D. 0.3

We see that the frequency of 0.3 matches choice D.

So, the frequency of the rr genotype is [tex]\( \boxed{0.3} \)[/tex]. The correct answer is D.