The us constitution set up three branches of government so that each branch could limit the power of the others. categorize each task according to which branch it limits, if any.

The U.S. Constitution has three branches of government namely: The Executive, Legislative, and the Judicial branch that act to check and balance each other, for example,  the writers of the constitution who craved for independence from Britain left it open for amendments (change). The first ten amendment comprising of the Bill of Rights was ratified four years after the constitution.
On 17th September 1787, the U.S. Constitution was adopted and it sets out three distinct branches of national government and provides power to each which serves as a check on the others. They consist of:
1. The Executive Branch: 
The President
-He/She is the commander in chief of the United States armed forces though only Congress can declare war.
- Appoints cabinet officers, Supreme Court Justice, and other officials who are subjected to Senate confirmation.
-Power to veto legislation

2.Legislative Branch:
Congress
There are two houses of Congress as provided by the constitution:
the House of Representatives and the Senate. Each state elects two Senators.
Congress has the power to make all federal laws, and its the house only that can introduce tax legislation. The Senate confirms or denies the President's appointment to the Cabinet, Supreme Court, and other key positions.

3. Judicial Branch:
The Supreme Court
The president nominates the Justice, is confirmed by the Senate and has the chance to serve in that position for life as long as he/she demonstrates "Good Behavior." The Supreme Court determines what the constitution means effectively.