What suspension component allows for pivotal and rotational movement of the wheel?

The ball joint is the component that facilitates pivotal and rotational movement of the wheel within a vehicle's suspension system. It serves as a crucial connection point between the steering knuckles and the control arms, allowing for the necessary movement required during steering and when the suspension compresses or rebounds over bumps. This joint enables the wheel to turn smoothly while also accommodating vertical movement as the vehicle travels over uneven surfaces.

In contrast, the other components listed serve different functions. The shock absorber primarily dampens the oscillations of the springs and helps maintain tire contact with the road, but it does not facilitate movement itself. The leaf spring is primarily designed to support weight and absorb shock, providing a stable platform rather than aiding in movement. The control arm connects the wheel hub to the chassis and provides a pivot point for the wheel, but its function is more about positioning and supporting the wheel than allowing for the actual movement that occurs at the ball joint.