What component pulls the support arm and block into the lowered position during ramp movement?

The component that pulls the support arm and block into the lowered position during ramp movement is the drawback cable. This cable plays a crucial role in controlling the movement of the ramp by ensuring that as the ramp is lowered, the support arm and block are drawn back into place smoothly and efficiently.

The functionality of the drawback cable is to provide the necessary force to counteract the weight of the ramp as it moves, allowing for controlled descent. This ensures that the ramp lowers safely without excessive speed or instability, which is important for both operator safety and the structural integrity of the ramp system.

In the context of the other options, guide wheels typically assist in the tracking and guiding of moving components but do not actively pull or lower them. Pull cables can be involved in various mechanisms but may not specifically relate to the lowering motion of a ramp. A counterweight, while it can influence movement by balancing forces, does not directly perform the action of pulling the support arm into the lowered position. Thus, the drawback cable is the most fitting answer, as it specifically addresses the mechanism required for that particular action during ramp movement.