Why do positive feed back mechanism required a external mechanism to stop it?

Positive feedback mechanisms amplify a process or response, leading to an increasingly greater effect. This can result in an uncontrollable situation if left unchecked, as the system can spiral out of control. Therefore, an external mechanism is required to provide regulation or inhibition, ensuring that the feedback loop does not lead to harmful or unsustainable outcomes. Such regulation helps maintain balance and stability within the system.