|When room temperature is increased, negative feedback inhibits heater (function).|
① Summer came. Room temperature is increased due to the summer heat. Heater increases room temperature. These are in the same direction (red).
② Since these are in the same direction, negative feedback inhibits (blue) the heater (function, such as by turning the power off). Because of this, the room temperature-increasing effect of the heater weakens, and the increase in room temperature (red upward unfilled arrow) disappears (increased room temperature decreases to the baseline).
This simply says, when room temperature is increased (during summer), heaters are not used. In the present "Step-By-Step Study of Life Sciences", let's call such control red→blue negative feedback.