Answer:
First one I already answered on the other post.
The Qb starts the play, gets the ball, and decides whether to hand it off or keep it to himself.
Now for the second one if your teacher asks why it's worded like that for the Qb to keep the ball. Look at his eyes, if he was handing the ball off he's looking at the runningbacks hands so there isn't a fumble, but if he's keeping it he's looking at the defense which is what he is doing.