This article (1) _______ on the game of American football, a distinct type of football that developed in the United States in the 19th century. It developed out of two other sports, soccer (2)_______
known as association football) and rugby football, each of which remains a separate sport with its own specific set of rules. American football differs slightly in (3) _______ and field size from a style of football (4) _______ mostly in Canada, called Canadian football. Other varieties of the game popular in (5) _______ parts of the world have Australian football and Gaelic football.