What connects the ends of the pinion gear and rack?

The appropriate connection between the ends of the pinion gear and rack is formed by tie rods. In a rack and pinion steering system, the pinion gear engages with the rack to convert rotational motion into linear motion. The tie rods serve as the link between the rack and the steering knuckles, allowing the movement of the rack to directly influence the direction of the wheels. When the driver turns the steering wheel, the pinion rotates, moving the rack either left or right. The tie rods facilitate this movement by connecting the ends of the rack to the wheel assemblies, ensuring proper steering response and vehicle control.

The other choices represent different components within a vehicle's structure and serve different functions. Drive shafts are primarily responsible for transmitting torque from the engine to the wheels. Control arms connect the vehicle's suspension to the frame and allow for vertical motion of the wheels. Wheel hubs are components that support the wheel assembly and allow it to rotate. While they all play essential roles in a vehicle's operation, they do not directly connect the pinion gear to the rack.