Legislative Branch: In Article 1 of the Constitution, the Legislative Branch is explained. The Legislative Branch is all about making laws, though they do have some other powers. The Congress, as it's called, consists of the Senate and the House of Representatives. The Senate has 100 members and a 6 year term, and the House has 435 members and 2 year term.
Executive Branch: The Executive Branch talked about in Article 2 of the Constitution. It's the part of our government that executes laws, or enforces them. The President and Vice President are the head of this branch, along with 15 other departments.
Judicial Branch: The Judicial Branch is the branch that is described in Article 3. This is the branch that focuses on judging based on the law. People in the Supreme Court are appointed, and serve till they die, retire, or are removed for bad behavior. There are no real requirements for age limit and citizenship in the Constitution. Instead, members of Congress and the Department of Justice have created their own qualifications.