What are the two conferences of the NFL called?

How many yards is the penalty for a false start? How many yards is the penalty for holding by the offense? How many yards is the penalty for unnecessary roughness? How many teams are in the NFL? How many divisions does each NFL conference have? What is the position of the player who snaps the ball to the quarterback? Which defensive position lines up deep in the secondary as the last line of defense? What is it called when a defender tackles the quarterback behind the line of scrimmage?