It would be "Communist demonstrations" that did not <span>help cause World War I, since communism really did not start to play a prominent role in Europe until later in the century. </span>
The correct answer is - natural selection.
This is a typical case of natural selection, where we have a group of people that have similar physical traits, that are selected and than isolated from any external influence, so with interbreeding they manage to keep their physical traits for generations to come and thus create a population that resembles their initial ancestors.
I would think
<span>C. By the amount of people who moved to the south during reconstruction
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To not be owned by England anymore
