Which theory of social change has been used most often to explain the collapse or decline of civilizations?

A. Evolutionary theory

B. Equilibrium Theory

C. Cyclical Theory

D. Modernization Theory,

A. Evolutionary theory. Since Darwin published the Origin of Species in the 19th century, interpreters have made wide ranging extrapolations of the theories to explain different social phenomena. For instance, Herbert Spencer adopted Darwin's evolutionary to society and called it Social Darwinism.