What is the primary role of the control arm in a suspension system?

The primary role of the control arm in a suspension system is to connect the wheel hub to the vehicle's chassis while allowing for vertical movement. This connection enables the wheels to move up and down in response to road conditions while maintaining proper alignment with the chassis. The control arm facilitates the suspension's ability to absorb shocks and bumps, contributing to a smoother ride and better handling. It is designed to pivot around a fixed point, allowing for controlled movement that helps keep the tires in contact with the road, which is crucial for safety and performance.

The other options describe functions that are either unrelated to the control arm or pertain to different components of the vehicle. For example, supporting the weight of the engine and adjusting steering alignment are functions performed by different parts of the vehicle's structure and systems entirely. Similarly, regulating tire pressure is related to the tires themselves rather than the suspension components.