fifteen (it could mean a team of fifteen players)
Basketball is a team sport with 5 players in it.
Volleyball is a sport that requires only 6 players per team.
Rugby Union is a full contact team sport. It is the game with most players in a single team. There are 15 players in each team. There is no sport in which a team has 16 members.
Basketball
football
There are many sports which have 5 players per team. One of them is Basketball.
Football has 18 player in a team.
None. A basketball team can have as many players as it wants to have, provided that it has enough jerseys.
someone who signs players
Soccer
A rugby union team has 15 players. A rugby league team (a slightly different sport) has 13.