-- If you go outside at the same time every night and look at
some familiar stars, you'll see each of them them move westward
at almost exactly 1 degree per night.
-- The reason for that apparent motion is the real motion of the
Earth in its orbit around the sun, at almost exactly 1 degree in
every 24 hours.
(average during a whole year is 0.9856 degree per day.)
One physical feature is a mountain.
Salt water is a homogeneous mixture or a solution.
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 :)
