During the four hundred years of Qin and Han dynasties, politics and culture pushed each other to form a complementary mechanism. The effects were: unity was considered reasonable, normal, and the division was considered illogical and abnormal. This trend created by Qin and Han culture, It has profoundly affected the history of China for the next two thousand years. The unification of the country has strengthened the speed and intensity of the integration of multiculturalism; the integrated unified culture has strong cohesion and centripetal force, which in turn increases political unification. What does this passage mean? ['Politics and culture are closely linked.', 'The influence of Qin and Han culture on future generations.', 'The Chinese culture has a strong centripetal force.', 'The premise of national unity is the unification of culture.']