Who is a president and vice president?
The President is responsible for implementing and enforcing the laws written by Congress and, to that end, appoints the heads of the federal agencies, including the Cabinet. The Vice President is also part of the Executive Branch, ready to assume the Presidency should the need arise.
The primary responsibility of the Vice President of the United States is to be ready at a moment’s notice to assume the Presidency if the President is unable to perform his or her duties. This can be because of the President’s death, resignation, or temporary incapacitation, or if the Vice President and a majority of the Cabinet judge that the President is no longer able to discharge the duties of the presidency.