Answer:
The executive branch has changed greatly since adoption of the Constitution. Many changes have been the result of constitutional amendments. ... Congress can affect presidential power because while the executive branch enforces the laws, Congress makes the laws in the first place. The Constitution explicitly assigns to the president the power to sign or veto legislation, command the armed forces, ask for the written opinion of his Cabinet, convene or adjourn Congress, grant reprieves and pardons, and receive ambassadors .