A localized solution is any system whose change of values of its variables can be represented as a series of points suggesting a straight line on a coordinate; hence, 'linear' for 'line'. More generally, a linear system is one in which small changes result in small effects, and large changes in large effects. In a linear system, the components are isolated and noninteractive. Real linear systems are rare in nature since living organisms and their components are not isolated and do interact. Compare with nonlinear system.