The Leader of the Government, who is ordinarily the leader of the party having the greatest number of seats in the House of Commons. Appointed by the Governor General, the Prime Minister selects the other members of the Cabinet and, along with them, is responsible to the House for the administration of public affairs.
A prime minister is the most senior minister of a cabinet in the executive branch of government in a parliamentary system. They are usually, but need not always be, a politician. In many systems the Prime Minister selects and can dismiss other members of the cabinet, and allocates posts to members within the Government.