If the frequency of a particular allele that is present in a small, isolated population of alpine plants decreases due to a landslide that leaves an even smaller remnant of surviving plants bearing this allele, then what has occurred? A. A bottleneck B. Genetic drift C. Microevolution D. A and B only E. A, B, and C are all correct.

Option-E

Explanation:

Genetic drift refers to the change in the frequency of the alleles in a small population over a short duration of time. This change in frequency is due to the random process like a natural catastrophe.

In the given question, the population of alpine decreased and resulted in the smaller surviving plant population. This changed the gene pool of the population and resulted in the genetic drift.

However, this also leads to the macroevolution as the process changes the population survival, as well as the bottleneck effect, is observed as the smaller gene pool survives and will reproduce.

Thus, Option-E is correct.