Every interaction you have with a basketball is affected by gravity. Gravity is the fundamental force of attraction between objects. Therefore, no matter if you are passing, dribbling, shooting, or dunking, the gravational force of the Earth is attracting the basketball down to the court floor.
When you shoot a basketball, you exert a downward force on the ball, causing it to travel in an arc as it approaches the rim. If you flip your wrist at the moment you release the ball, the ball will spin from bottom to top, as it moves through the air. This spin creates a difference in pressure, and generates an upward force. This force counteracts the downward force extorted force by gravity, adding lift to your shot increasing your range and improving the angle of entry of the ball into the net.
Each time you dribble a basketball you exert a downward force on the ball with your hand. The ball then collides with ground and bounces back up. The higher the air pressures of the ball, the more elastic the collision between the ball and the ground. For this reason, it's more important to use a well inflated ball when playing.
When you pass a basketball, you exert a forward force toward a target player, much like when shooting. The ball travels in an arc rather than a straight line. If you do not account for gravity, the destination of your pass will be lower to the ground than anticipated, which will make your pass difficult for the target player to handle. For this reason, you must exert a slight upward force and pass the ball slightly higher than the target to compensate for the downward force of gravity.