Which system automatically adjusts its control without manual intervention?

A closed loop system is designed to automatically adjust its control based on the feedback it receives from the output. In these systems, sensors monitor the output variable and provide this information to a controller. The controller then compares the measured output to a desired setpoint. If there is any deviation from that setpoint, the system makes necessary adjustments to bring the output back to the desired level without requiring any manual intervention.

This ability to self-regulate makes closed loop systems effective in maintaining system stability and responding dynamically to changes in conditions or disturbances. The continuous feedback loop is essential for optimizing performance and achieving desired operational parameters effectively.

In contrast, open loop systems do not incorporate feedback, meaning they cannot make adjustments based on the output. Feedback systems, while closely related, typically refer to the component that provides the information back to the controlling part of a closed loop system. Manual control systems rely on human input to adjust operations, thereby lacking the automation that is a hallmark of closed loop systems. Thus, the automatic adjustment capability of closed loop systems distinguishes them as the correct answer in this context.