Football is a team sport played on a field measuring 100 yards long and 160 feet wide. The game features two teams consisting of eleven to 18 players. One team carries the ball and the other defends it. There are several variations of the game.
Each team has a defensive line, which consists of three to six players. They attempt to tackle the quarterback and running backs. Some offensive players, like the wide receivers, are also called defensive players. Their job is to intercept a pass or prevent the other team from advancing the ball.
The offensive line is comprised of five players. They clear the way for the runners, while also protecting the quarterback.
The offensive team gets first down by running or passing the ball. When the ball goes out of bounds, the play ends.
When the offensive team scores, it is called a touchdown. To score an extra point, the team must catch the ball in the end zone. Alternatively, the team can kick the ball through the goal posts. In the NFL, the offensive team can try for a two-point conversion.
In the NCAA, a player is considered down if any body part hits the ground. For example, if the quarterback is ruled down due to a foul, any other player is also considered down.
Whenever a football play fails to produce a positive outcome, the official blows a whistle. Occasionally, a team can delay a play. After a certain amount of time, a new play is started.