Final answer:
The frequency of the heterozygous genotype (Dd) in the frog population is found by dividing the number of Dd individuals (18) by the total population (60), resulting in a frequency of 0.30. The correct answer is option A. 0.30.
Step-by-step explanation:
To calculate the frequency of the heterozygous genotype in a population of frogs, we must look at the number of individuals with the heterozygous genotype (Dd) and divide this by the total number of individuals in the population. In this case, there are 18 (Dd) individuals, 30 (DD) individuals, and 12 (dd) individuals, making the total number of individuals 60 (30+18+12).
The frequency of the heterozygous genotype is the number of (Dd) individuals divided by the total number of individuals in the population:
Frequency of Dd = Number of Dd individuals / Total number of individuals
Frequency of Dd = 18 / (30+18+12)
Frequency of Dd = 18 / 60
Frequency of Dd = 0.30
Therefore, the correct option for the frequency of the heterozygous genotype is A. 0.30.