This heating system maintains room temperature at or near a particular value, known as the . 2. you open the window, and a blast of icy air enters the room. the temperature drops to 17 degrees celsius, which acts as a to the heating system. 3. the thermostat is a that detects the stimulus and triggers a response. 4. the heater turns on, and the temperature in the room until it returns to the original setting. 5. the response of the heating system reduces the stimulus. this is an example of feedback. 6. the way this heating system maintains a stable room temperature is similar to the way an animal's body controls many aspects of its internal environment. the maintenance of a relatively constant internal environment is known as .