Final answer:
The three main branches of the federal government are the Legislative, Executive, and Judicial branches, with Congress being part of the Legislative branch.
Step-by-step explanation:
The three main branches of the federal government in the United States are the Legislative, Executive, and Judicial branches. Congress is part of the Legislative branch. Article I of the Constitution establishes Congress as the branch responsible for making the laws for the nation. The Executive branch, as defined in Article II, is responsible for implementing and executing the laws, and it is headed by the President. The Judicial branch, detailed in Article III, is charged with interpreting the laws and ensuring that they are applied fairly.