A systems approach subdivides a complex system into a series of interrelated component parts that are linked via transfers of mass and/or energy.

A change in any part of the system, for example in the operation of a particular process, can lead to changes in the whole system.

Negative Feedback: If one element changes because of some outside influence, this upsets the internal equilibrium and affects other components of the system

Positive Feedback: By a process of feedback, the system adjusts to the change and regains equilibrium