Final answer:
The full authority of government is vested in separate branches and is not held by a single entity; the President of the United States has executive powers but does not gain full legislative powers when Congress is not in session.
Step-by-step explanation:
When the supreme governing body is not in session, the full authority of government is not vested in any one entity that combines both legislative and executive powers. In the United States, according to Article I, Section 1 of the U.S. Constitution, all legislative powers are vested in a Congress, which consists of a Senate and House of Representatives. Although the President of the United States has executive powers and the ability to make certain decisions when Congress is not in session, the President does not have the full authority of government.
The power of governmental institutions, including the extent of the president's powers when Congress is not in session, is subject to both de jure (legal) and de facto (in practice) rules. Moreover, the president can veto legislation approved by Congress, but Congress has the power to override a president's veto with sufficient votes. Therefore, the full authority of government is shared among separate branches, even when the legislative body is not active.