Footballers Cant Challenge A referee's Decision. If he does and gets Carried away with it the player receives a booking! And In tennis its simply too keep the game fair. Like Now there is reviews in Cricket!
American football has a few referee's at every game to monitor each play at all times.
22. 11 per side. not including the referee
If you are talking about soccer than in total there are 23 (including the referee and 11 a side) but if you are talking about American football then i don't know.
Referee
yellow
the first to play soccer (football) was the roman they would have hundred of players but no referee
A yellow card in UK football is issued by the referee for a players first offence.
A referee can only show cards to players, and since the referee himself is not a player he cannot receive red cards. A referee may remove themselves of their duties if they are unable to continue.
It depends on the sport. The only sport I can think of immediately that uses both a referee and an umpire is American football, where the referee is the highest ranking official.
American Football referees
A referee usually controls a football match
cheer leaders, classmates, parents, referee, players, coach, band members