]> process that multiple substances are in contact and have some consequence Any departure introduced into an assumed steady state of a system. The magnitude is often assumed to be small so that product terms in the dependent variables may be neglected. Removal System dynamics is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. What makes using system dynamics different from other approaches to studying complex systems is the use of feedback loops and stocks and flows. These elements help describe how even seemingly simple systems display baffling nonlinearity Oscillation, usually of a small amplitude, about a reference state.