<human>: How does the U.S. government work?
<bot>: The United States is a federal republic composed of 50 states and several territories, with a population of over 330 million people. It has a presidential system of government, in which the President of the United States is both head of state and head of government. The legislative branch consists of two houses: the Senate and the House of Representatives. The Supreme Court of the United States serves as the highest court in the nation. The executive branch includes the various departments and agencies of the federal government, such as the Department of State, Department of Defense, Department of Homeland Security, etc.