Answer:
1. Popular sovereignty
2. Power, Federal
3. Laws
Step-by-step explanation:
1. Ensured Popular sovereignty: idea that political authority resided in the people.
Popular sovereignty is a political concept that power or authority resides in the people. People hold the authority of choosing their rulers through elections. This concept regards people of a country as source of power and might as Benjamin Franklin once wrote, "In free governments, the rulers are the servants and the people their superiors and sovereigns".
2. Provided for federalism: sharing of Power/Authority between states and National/Federal government.
Federalism is the system of shared power or authority or government between national/federal and the state governments. The states and the federal government have both exclusive and concurrent powers. The Constitution allows specific powers to be the domain of a federal government, and others are specifically reserved to the state governments to keep balance of power and avoid clash of authority.
3. Required states to obey laws of the federal government.
The supremacy clause in the US constitution states that federal law is the supreme law of the land and all the state governments are supposed to obey the federal law.
However, states has the right to challenge or invalidate any federal law if state finds a federal law to be against the US Constitution.