The systems approach is about the interrelationships of all elements. Systems theory stresses the importance of the environment. Open systems receive inputs from the environment. Business is an open system dependent on the environment for inputs. Closed systems are self contained, independent, discreet.
Closed systems receive no inputs.
They are either dead or a sort of perpetual motion machine. Boundaries separate the system and the environment. The issue of boundaries addresses the question of what is the system and what is the environment. Where does one end and the other begin. Boundary specification is important to considerations of control.