Define: social stratification and social inequality. Then, using functionalism and conflict theories, explain the reasons and justifications for the persistence of social inequality and social stratification in human societies. Use Kuznets' Curve to back up your discussions while identifying those societies which have experienced various degrees of social inequality. In your answer, use concepts such as: social placement; ascribed status; achieved status; closed and open systems of stratification; social mobility; and, social differentiation.