The idea of the us gaining all land from one seaboard to the other is called manifest destiny the us gained these lands through several different purchases, annexations, and agreements such as the annexation of texas the treaty to give the us land in oregon below the 49th parallel and so forth.
The answer is....
The 3rd law
There were three principles created by Chief Justice John Marshall
1: the constitutional is the supreme law of the land
2: the court has the power to rule that a law is unconstitutional
3: in the event of a conflict between laws, the constitution MUST be followed.
Answer:
it's so that one branch cannot take control of the whole government
Explanation:
they want a fair government so they split the power
