Final answer:
A modulating thermostat is equipped with a thermistor, which is used to sense and control the temperature by changing resistance.
Step-by-step explanation:
The question is inquiring about a specific component included in a modulating thermostat. A modulating thermostat is a device that precisely controls the temperature to maintain a comfortable and steady indoor environment, similar to how the human body maintains a steady state called homeostasis. The accurate answer to this question would be a thermistor. A thermistor is a type of resistor whose resistance varies significantly with temperature, used for temperature sensing and control in a thermostat. They are not typically associated with piezoelectric devices, solenoid relays, potentiometers, or receivers in this context.