How did the united states manage to expand its territory across the continent

So, the United States wanted to find more opportunity in different places than where they were currently at. Of course they would go and expand their territory. United States pretty much bought out their way across the continent, with New Orleans and West Florida for $10 million as an example. They possibly fought for a bit of it, but most of it was bought out. :)

-Mabel <3

Manifestation, or manifest destiny. The expansion of a country.

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]

a and b because with the other three, they simplify to something else.