The achievements of the Tang and Song Dynasties include __________.

The Tang and Song Dynasties were periods of major innovation and cultural development in China. Gunpowder was invented in China, and Confucian ideas became influential again, especially during the Song Dynasty. The caste system developed in India, while the unification of Japan and the spread of Islam throughout China were not achievements of these dynasties. Therefore, the best answer is the invention of gunpowder and the growth of Confucianism.

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