You cannot block a shot after it starts descending toward the basket or touches the backboard. On offense, you can’t touch a live ball on or inside the rim.
Ultimately, these ten rules—dribbling, traveling, double dribbling, carrying, scoring values, the shot clock, out-of-bounds, personal fouls, team foul limits, and the five-player team structure—create the balanced environment that makes basketball a global phenomenon. They ensure that while the game is played with the body, it is won with the mind. 10 basketball rules
Each team has 5 players on the court at a time (point guard, shooting guard, small forward, power forward, center). Unlimited substitutions are allowed, but only during dead balls. You cannot block a shot after it starts