Compare and contraste: the social classes in tang and song china

Tang and Song were Chinese Dynasties.

The social classes in Tang and Song had some similarities, they brought the return of the examination system, the progress of urbanization, reemergence of Scholar Gentry class  and improvement of bureaucracy. The Tang Dynasty was ruled to 618 and 907, The Song Dynasty from 960 to 1279. They were ruled in different territories.

presidency should be the title