Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?
a. mutationb. nonrandom matingc. genetic driftd. natural selectione. gene flow

The correct answer is C. genetic drift

Explanation:

Genetic drift occurs in a small population due to the change in the allele frequency in a population due to random sampling. For example, in the bottleneck effect, most of the individual in the population die because of the natural calamities or disease which reduces the population size.

Therefore it this condition the small population have less genetic variation than the older big population because of loss of several allele due to killing of most individuals of the population in the calamity. Therefore the gene pool becomes small in smaller populations due to genetic drift. So the right answer is C. genetic drift.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.