It would be the "Necessary and Proper Clause" that establishes many implied powers of Congress, since this allows Congress to do whatever is "necessary and proper" to keep the United States functioning.
in the beginning, slavery mostly
baron de Montesquieu admired a mixed government due to the division of power between the various divisions. He admired governments with the monarch as the head and a body representing the people that also acted to check the powers of the monarch to avoid abuse
Idk but its some kinda law
The continental line is the name of it, if thats what you were asking, Hope it helped! (:
