Rankings change weekly during the season
I have to assume that you are talking about NFL professional players. Since most of them come from college football teams, most have a college education.
There are approximately 119 College Football teams.
USC
College bowl games are college football games. The only people that may compete in college bowl football games are the players from each of the college football teams.
All college football teams have the exact same number of players dressed for each game (defined by NCAA rules).
way less than football because football teams have more players on one team. Basketball has usually 9 to 15 players compared to 53 players on a football team.
Most NFL teams will have open tryouts. Including players who were not drafted, players from semi-pro teams, free agents and players from other sports. Notable NFL players who never played college football are Antonio Gates (San Diego Tight End who played Basketball in college) and Carlton Hasselrig (Pittsburgh Linebacker who Wrestled in college).
I think it's 105 in Division 1A.
1 drake university of Iowa
Football
where teams of a certain ranking battle in a tournament to see who win a championship usually BCS but this rule is not yet enforced in college