Why did so many early civilizations arise near river valleys

Amain reason most irish immigrants came to the united states in the mid-1800s wasa) to find jobs as skilled workers.b) to escape a potato famine.c) to live in less-crowded conditions.d) to escape religious persecution.

Is the idea of containment relevant to american forge and policy today why or why not

Why did metternich think nationalism threatened the austrian empire?