We will have that projectile motion works in an almost exact way as the theory tells us; the difference lies in the fact that the theories are modeled for a perfect system, but real life is not perfect and there are incredibly small variables that affect the movement of objects.
Now, in the case of basketball for example an object will have a mass, this object will be thrown with an initial velocity, acceleration and angle; now all of this affects the parabolic motion of the object. When in movement there are other forces the object has already been subjected to, like gravity that "pulls" on the object every moment, but when thrown then starts to bring the object to the ground.
The general form of the projectile movement is the one presented in the graph; but in real life there are factors that change the behavior slightly, such as friction with the medium, pressure, temperature, inertia of the object, another external forces, and so on.