a defender stops the ball from going into the goal
the defender stand in front of the goalkeeper and tackles
A center snaps the ball, blocks any defender in his area making a way towards the quarterback, an open eligible receiver and is a guaranteed bet for yards. And the best player on the field.
A few of the positions pass the ball but the biggest would be the quarterback. The quarterback passes the ball to a linemen, and is the first throw of the game!
theres the center, 2 receivers, 2 halfbacks, and a quarterback
An option in football is play that attacks a specific defender by leaving him unblocked and forcing him to have to defend two different players. One of the players is usually the quarterback and the other is a running back. The quarterback will read the reaction of the defender and either give or keep the ball. The offense has two "options" on the play for who can be the ball carrier. Triple option plays involve a third possible option for the offense.
The defender usually depends on the sport. In soccer (football) the defender is the one that protects the goal. I don't know much about football (American Football)
Defend
A pro football because the quarterback is used to throwing the pro football and not a Nerf football.
The quarterback throws the football in football
Flag football or touch football
Defender
A football position
runningback