An area that has some kind of a unity in terms of terrain, climate, government, or language can be called a what?

Region i think sorry if I got it wrong doe

Quizlet has the answer

It is the doctrine that the us had the right and duty to expand throughout north america. it just means they believed they had the right to expand westward and they did! they stated with the 13 colonies and then they kept moving gaining different territories throughout the years