Explain one reason you think that it would have been more common long ago to find nation-states than it is today.

 Back then, most people did not consider themselves part of a nation; they rarely ... At the same time, the rulers of states frequently had little control over their ... over more land, eventually expanding to cover much.

Explanation:

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ExplanatiBack then, most people did not consider themselves a part of a nation. At the same time, the rulers of states often had little control over their land.on:

just finished this it is b. centrifugal force