Final answer:
In homeostatic feedback loops, the control center is the component that knows the set point for a variable and maintains homeostasis by using negative feedback loops to adjust the variable back to the normal range.
Step-by-step explanation:
The component of a homeostatic feedback loop that knows the set point for a variable is the control center. In a homeostatic control mechanism, the control center is responsible for monitoring and maintaining variables within a normal range, which is known as homeostasis. It receives data on the variable's current state from the sensor, compares this data against the set point, and, if necessary, sends signals to the effector to initiate a response that adjusts the variable back towards the set point. This is crucial for keeping all of the body's internal variables within normal ranges and is achieved using negative feedback loops.