Eli5: what does a quarterback look for when teams get to the line of scrimmage? And what does he do before the snap?

Question

Eli5: what does a quarterback look for when teams get to the line of scrimmage? And what does he do before the snap?

In: 2

Answer 1

The formation of the defense. If the qb gets to the line and immediately realizes that their defense is set up perfectly against their offenses play, the quarterback may choose to alter the play on the line.