Please describe how situational awareness is a driver for detection and response controls.

Much of the security efforts of the past have been centered around prevention and protection. The increasing sophistication of cyber attacks have shown that no controls are 100% effective, and some compromises do occur. There is a rising realization that in addition to considering prevention and protection, controls that address detection and response are necessary to improve security posture. Please describe how situational awareness is a driver for detection and response controls.