Which line separates the field of play from the end zone?

The goal line is the critical line that distinguishes the field of play from the end zone. It serves as the boundary that must be crossed by the ball for a team to score a touchdown. A touchdown is achieved when the ball, carried by an offensive player, crosses this line while in the player's possession, or when a pass is completed in the end zone.

The end line, while it marks the back boundary of the end zone, does not separate the field of play from the end zone; it is instead the furthest point behind the goal line. The sideline defines the lateral boundaries of the field but does not play a role in differentiating the end zone from the field of play. The term "touchdown line" is not used in NFHS terminology; therefore, it is not a valid option.

Overall, the goal line is essential not only for defining the areas on the field but also for determining scoring opportunities, making it vital for understanding the dynamics of football gameplay.