A system can be biological (human body), physical (machine) or social (commercial organizations, voluntary bodies and etc.). Social systems are man- made systems and the relationship of the sub-systems in them is the most critical element. In addition, since social systems include human beings, values, their beliefs, attitudes and perceptions have an important bearing on the working of the system. This aspect is dealt along with motivating and leading. A system could be closed or open. A closed system is self- enough and self-regulatory and has no interaction with the environment in which it exists that was shown in below figure. The feedback from the output triggers off a control mechanism which then regulates the input to bring the output to the desired level.
Figure: A Closed System