If you are talking about the line ofscrimmage or the First down line it is animated.
When you get 10 yards ahead of the original line of scrimmage
The defensive line in American football has many jobs. First is to attempt to break through the opponents offensive line in order to tackle the quarterback. Others on the defensive line are given the task of running down field with a receiver to try to intercept the ball.
The blue line is the line of scrimmage, or where the offense started the play from. Conversely, the yellow/orange line is where they need to get to for a first down.
That line is called the line of scrimmage.
The yellow line that you see on your TV screen is not on the football field. It is only a visual reference for those of us watching the game on TV so we can see how far the offense needs to go to get a first down.
If the offense recovers the fumble and advances it beyond the original first down line, yes, it is a first down. If the ball is not advanced past the original first down line then the next play is the down after the one that the fumble occurred on. For example, if a running back fumbles the ball on second down and an offensive line man recovers the fumble but does not advance the ball beyond the original first down line, it is then third down. If the defense recovers the fumble, then it is an automatic first down wherever the player that recovered the fumble is downed.
A block down field beyond the line of scrimmage
Yes, the ball would be spotted the farthest the player went, unless they went backwards on their own will.
That is the line of scrimmage, the line in which the team with the ball begins their play on. it may also be the 1st down line
The first end zone line, ususally referred to as the goal line.
If, after gaining a first down, a player is tackled at the one yard line, then it would be 1st and 1. Some may consider this 1st and goal.