SECTION 1. Live Ball - Dead Ball 

Article 1 - Dead Ball becomes Alive 

For the next down the ball shall be put in play at the spot midway between the side lines, laterally in line with the spot where the ball was when it became dead by rule, or at the spot where the ball has been placed following completion of an accepted penalty or to award a new series.
After a dead ball is made ready for play it becomes a live ball with the start of a legal snap. A ball snapped before it is made ready for play or is illegally snapped remains dead. A foul before the ball is snapped (delay of game, encroachment, false start, disconcerting signal, illegal blitzer signal) will cause the ball to remain dead.

Article 2 - Live Ball becomes Dead 

A live ball becomes dead by rule and an official shall sound a whistle when:
a. The ball is out of bounds.
b. The runner is out of bounds.
c. Any part of the runner’s body except their hand or foot touches the ground. AR 4-1-2-I
d. A runner simulates placing the knee on the ground.
e. A pass or fumble (forward or backward) strikes the ground.
f. A teammate of the fumbler touches the ball.
g. A player with fewer than 2 flags is in possession of the ball. AR 4-1-2-II
h. A player with flags not positioned correctly is in possession of the ball and the player themselves is responsible.
i. A touchdown, touchback, safety or successful try occurs.
j. A foul which causes the ball to become dead (e.g. illegal kick or delay of pass) occurs.

On an inadvertent whistle by an official, the ball becomes dead and the team in possession may elect either to put the ball next in play where it was declared dead or to replay the down.