I'm Barack Obama and i'm the president of the United States and I work for the Executive Branch. My job is to make sure the laws are carried out, commands the armed forces, and I can veto, or reject laws passed by the Congress.
I'm a senate and I work with the house of Representatives and I work at the Capital. I work for the Legislative Branch. My job is to make laws, establish laws, and I can reject vetoes.
I work at the supreme court, and other Federal Courts. I work with the Judicial Branch. My job is to interpret the laws, decide if the laws follow the construction, and I can stop laws that are against the Constitution.