Fig $1$ A feedback control system.

a$)$ See Figure $1,$ What sort of feedback control system is in use in this instance, how did you know what sort it is$?$

b$)$ Explain how it works to control the temperature in the room. What are the advantages and disadvantages of this method of control?

c$)$ What improvements would you recommend if the requirement has changed and now the temperature needs to be under much more close tolerance?