What distinguishes a manual control from an automatic control?

The distinction between manual and automatic controls lies fundamentally in how the two systems operate. Manual controls require direct user interaction for operation, meaning that someone must actively engage with the device to initiate or modify its functioning. This human intervention is essential; the system does not work without the user's input.

On the other hand, automatic controls are designed to self-regulate without continuous human oversight. They perform functions based on pre-set parameters, sensors, or programmed responses, allowing them to adapt and respond to changes in the environment or system dynamics independently. This autonomy is a key feature that sets automatic controls apart from manual ones.

By understanding this essential operational difference, it becomes clear why the correct answer highlights the interactive nature of manual controls compared to the self-regulating characteristics of automatic systems.