Complex sentence: If the ball falls to the ground it is considered a touchback, if on fourth down you feel that you are not close enough to have a good chance at scoring a touchdown then you can attempt a field goal for 3.
Split into simpler sentences: If the ball falls to the ground it is considered a touchback. If on fourth down a player feels that they are not close enough to have a good chance at scoring a touchdown then they can attempt a field goal for 3.