Consider the diagram below showing the gene pool of a population over 20 generations - VCE - SSCE Biology - Question 26 - 2019 - Paper 1

In Generation 1, the population is represented by a mixture of heterozygous and homozygous individuals. Since both R and r alleles are present, it is plausible that their frequencies are approximately equal at this stage. As the generations progress, due to selective pressures or genetic drift, the frequency of alleles may change. The fact that by Generation 20, we see a predominance of homozygous individuals for the r allele suggests an imbalance in allele frequencies developed over time. Therefore, statement C is right as the initial frequencies of alleles in Generation 1 differ in later generations.