No he is not
No it is not allowed.
Yes a player can be substituted at half time, as the ball is not in play.
In Phase 10, a player is allowed to skip their turn twice before being penalized.
In Phase 10, a player is allowed to skip their turn up to two times before being disqualified.
In volleyball, a libero is not allowed to serve. The libero is a defensive specialist who can replace any back-row player without prior notice, but their role is limited in terms of attacking plays, which includes serving. However, if the libero is substituted out for a player who is allowed to serve, that player can take their place to serve.
In tennis, a player is allowed one bounce to return the ball before it hits the ground a second time.
When a player has been substituted, he cannot be placed back in the game. The only time a player can stay in the game is if he is moved to another fielding position. The moment he is removed from the batting lineup, he is removed from the game. In the American League, the pitcher is not in the batting lineup, but the moment he is substituted on the mound he is out of the game.
No. Once a player is substituted for, they may not reenter.
No. Once a player has been substituted for, he cannot re-enter the game under any circumstances.
In fastpitch softball, any player removed from the game and substituted by another player is allowed on re-entry. Some sanctioning bodies also allow for a courtesy runner for the pitcher and the catcher. Using a courtesy runner does not follow the substitution rule. In baseball, any player removed from the game is out. Period. No re-entry allowed.
No, a basketball player is not allowed to throw the ball up in the air before attempting their foul shot. Players are able to do any preparation that will help them, but are not allowed to release the ball into the air before shooting.
In table tennis, each player is allowed two serves before the opponent gets a chance to serve.