How many timeouts does each NFL team get per half?

How long is an NFL playing field between the goal lines? How deep is each end zone on an NFL field? How many downs does an offense get to advance the ball 10 yards? How long is each quarter in an NFL game? 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?