Answer:
The correct answer would be - marbles represent alleles for a particular trait that has an allelic frequency of 0.5 in this simulation.
Step-by-step explanation:
In this given representation or simulation to illustrate genetic drift, a student used marbles of different colors. She used 20 red and 20 yellow marbles in a population of 40 individuals. In this simulation, she used each marble color red and yellow to represent the allele for a particular trait.
That means red marbles represent alleles that are specific to a trait of a gene and similarly yellow marble represents another trait of the same gene. It is also represented that both alleles are present in the same number which means they have alllelic frequency of 0.5.