6. reproductive separation may result in the of two different species.

Evolution or speciation of two different organisms.

Explanation:

Reproductive separation or isolation is a process that involves the separation of populations of the same species that prevent them from interbreeding with each other and reproducing offsprings. These reduce the ability of different species to produce offsprings and cause a reduction in gene flow.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.