To determine the percentage of individuals expressing the recessive phenotype who are homozygous recessive, you can follow these steps:
1. Identify the total number of individuals: You start with a population of 300 individuals.
2. Determine the number of individuals expressing the recessive phenotype: According to the problem, 117 individuals exhibit the recessive phenotype.
3. Calculate the percentage of individuals expressing the recessive phenotype who are homozygous recessive:
- First, divide the number of individuals showing the recessive phenotype by the total number of individuals. This gives the fraction of the population that is homozygous recessive.
- Next, to convert this fraction to a percentage, multiply the result by 100.
[tex]\[ \text{Percentage of homozygous recessive individuals} = \left(\frac{\text{Number of recessive individuals}}{\text{Total number of individuals}}\right) \times 100 \][/tex]
4. Using the given numbers:
[tex]\[ \text{Percentage} = \left(\frac{117}{300}\right) \times 100 \][/tex]
5. Simplifying this expression:
[tex]\[ \left(\frac{117}{300}\right) \times 100 = 39 \][/tex]
So, the percentage of individuals who are homozygous recessive is [tex]\(\boxed{39\%}\)[/tex].
The correct answer is:
D. 39%
