1. The problem statement, all variables and given/known data Genetic drift play an imp role in: a. Large population b. Small population c.Bottleneck population d. Both b and c 2. Relevant equations Genetic drift is the change change in the allelic frequency due to random sampling. 'Small populations are more susceptible to genetic drift than large populations, whose larger numbers can buffer the population against chance events.' (boundless) Now Bottleneck population, the term is not a standard one I think. However population bottleneck ' is a sharp reduction in the size of a population due to environmental events (such as earthquakes, floods, fires, disease, or droughts) or human activities (such as genocide).' (wiki) May be the author of this question intended the reduced population, with the individuals that survived, so it should be small. 3. The attempt at a solution The answer's d ? Note: I have a couple of threads unresolved here. I would resolve them as soon as I find some time, I'm in the mid of a series of exams and will be free by the 2nd/3rd week of next month.