The right answer is B- create a bottleneck effect, reducing genetic diversity.
A population bottleneck (also known as a genetic bottleneck) is, in the study of biological evolution, an event corresponding to the fact that a substantial proportion of the population of a species disappears or is prevented from to reproduce.
Population bottlenecks (or bottlenecks) thus reduce genetic diversity, and hence the ability of people to adapt to new environmental constraints such as climate change, or a decline in available resources.
B is the answer. A bottleneck effect occurs when a large, genetically diverse population suddenly experiences some catastrophic even and declines to a very low population.
