What is a state in the context of world regional geography?

When air at the surface diverges, airflow above must diverge, regardless of hemisphere converge in the northern hemisphere but diverge in the southern diverge in the southern hemisphere but converge in the northern converge, regardless of hemisphere?

The creation of the trans-siberian railway allowed people to travel across russia. how could this railway impact russian culture?

What border separates sonora and chihuahua national border state border physical boundary natural boundary