Who is in charge of the executive branch?

Why this is the answer

The executive branch is the one that carries out, or executes, the laws Congress passes, and the President heads it. In this system the same person is both head of state and head of government. The powers that come with the office include signing treaties with other countries, selecting the ambassadors who represent the United States abroad, naming the top leaders of the federal departments, setting national policy and proposing laws to Congress. When a seat on the Supreme Court opens, the President names the new member. Answer with the office, not with the name of whoever holds it. Memory hook: the executive branch executes the laws, and that is the whole job.