Sate the responsibilities of Air Traffic Control (ATC), FSS, Control Tower, APCH, and Air Route Traffic Control Center (ARTCC).
ATC: Agency that enforces FAR part 91 and approves flight plans and grants clearances
FSS: briefings, en route comms, relay ATC clearances, originate NOTAMS, broadcast aviation weather, receive and process flight plans, provide flight following, monitor nav aids.
CT: Responsible for the safe, orderly and expeditious flow of traffic operating on and in the vicinity of an airport. Consists of Clearance Delivery, Ground and Tower.
APCH: Controls IFR traffic (Also Departure)
ARTCC: Controls IFR traffic en route between terminal areas.