Since the two populations of squirrels cannot adaptations favored in one population are not shared with the other
population's
Generation after generation, through multiple
events,
the two populations become
genetically similar
While the populations independently evolved on separate sides of the
river, allopatric speciation occurred, which is a
event.

mountains can affect the climate of nearby lands. in some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert. much of airborne moisture falls as rain on the windward side of mountains.

explanation:

not sure if this what   you'r looking for would be percent composition

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.