The offense is allowed up to ten players on the line of scrimmage, need one to receive the ball from the center. But the offensive is required to have a minimum of seven players on the line of scrimmage. Defensively all eleven can play on the line of scrimmage.
In tennis matches, players are allowed three challenges per set to challenge a line call made by the umpire.
Tennis players are allowed to make three challenges per set using the Hawk-Eye system to review line calls.
six players are allowed
6 players are only allowed.
10
9
there are 10 to11 players allowed
There are 11 players allowed on the field for each team in an NFL game.
15 players at least
The offense must have 7 players on the line of scrimmage.
The whole team.
In basketball, there are five players from each team allowed on the court at one time.