Final answer:
An illegal forward pass that strikes the ground is ruled a dead ball, ending the play, and is usually accompanied by a penalty against the offending team.
Step-by-step explanation:
When an illegal forward pass strikes the ground, the correct answer to the student's question is that it's a dead ball. In American football, if a forward pass is illegally thrown (for example, if the passer is beyond the line of scrimmage when he throws it, or if it is the second forward pass on the same play), the ball is immediately dead upon touching the ground, and the play is over. Additionally, the team that committed the violation is usually penalized five yards from the spot of the foul, and if it was a second forward pass, a loss of down is also applied.