Answer:
d. earths rotation on its axis
A biggie: the transcontinental railroad. Because it would economically improve wherever it was, both the North and the South competed for the railroad to be in their respective territory, evidenced by the Kansas-Nebraska Act and the Gadsen Purchase and induction of California as a free state in 1860.
In addition: people could get land cheap because it was abundant and might leave to start afresh economically.
There's other stuff I can't remember as clearly, but there's a little and I hope it helps :)
1. The protection granted by a nation to someone who has left their native country as a political refugee.
2. An institution offering shelter and support to people who are mentally ill
A region based on common properties such as population is called
<span>a </span><span>formal region</span>
