The document that gives the reasons for the separation of the colonies from Britain is
Common Sense.
o the Albany Plan of Union.
O the United States Constitution.
o the Declaration of Independence.

C.the declaration of independence

Explanation:

that is the answer

checks and balances are needed to keep the government running smoothly, they allow the three branches of government to overrule one another so that one branch of government does not become too powerful.

sorry i really dont know