What impact did Japan’s geographic barriers have on civilization? The different islands became separate countries.
People spoke the same language throughout the islands.
Different regions developed different traditions and cultures.
Villages became dependent on one another for specific resources.

Different regions developed different traditions and cultures.

Explanation:

This is because some parts of Japan were on Islands or perhaps even hindered by mountains. With no other influence, they often developed their own traditions. ofc now and later they could travel and the like, but I assume this is in regard to older Japan. I can't really explain that well but if my answer is wrong I am so so sorry!! :(

d.)   when the us left nato after the end of the cold war and they had to evolve to focus on more humanitarian measures with the smaller budget