True, if this is about WW1 the germans rapidly moved through Belgium ignoring thier neutrality in the conflict.
They knew the Greek idea of direct democracy. While they didn't necessarily apply the idea in their political system directly, they did apply some ideas that were shared with the Greeks that made the Roman political system more stable and better in the end.
<em>The best answers for me, the best geographic features that encourage movement would be Plains and Mountains.
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<em>Plains is a type of geographical form, wherein you could see a land flat area. Plains are great location for fields, trees, crops and domesticated animals. Since the area doesn't have much obstacles rather than trees and animals and maybe some rocks, people can easily manipulate movement in any form to this area. </em>
<em>Meanwhile mountains can be a good choice for movements as well. Mountains are type of geographical form, which is often huge and located above the grounds. The elevation of it's form are mostly in meters and feet high. Mountains are normally has limited scope and can support wildlife and forest lives. Movement can be facilitated on mountains. But it is much slower compared to plains, since there are more hindrance on it (like trees, huge rocks and animals).
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The correct answer is a. evolution.
Darwin was the scientist behind the theory of natural selection, one of the main mechanisms behind evolution (next to sexual selection).