Question

What are the main duties of the vice president?

to replace a president who leaves office and to fill in as needed
to advise the president on foreign policy and to negotiate with foreign countries
to develop military policies and to plan responses to national security
to advise the president and cabinet and to represent the United States in legal matters

Answer 1

The first option is correct: to replace a president who leaves office and to fill in as needed.

Brief clarification: The vice president’s constitutional duties are to succeed the president if the president dies, resigns, or is removed, and to serve as acting president under the 25th Amendment when the president is temporarily unable to serve. The VP also serves as President of the Senate and can cast tie-breaking votes, and performs other duties the president assigns.