Final answer:
The achievements of tea production expansion and the introduction of fast-growing rice during the Song Dynasty in China (960-1280) had a significant impact on commercial activity and the standard of living for ordinary people.
Step-by-step explanation:
The achievements of tea production expansion and the introduction of fast-growing rice during the Song Dynasty in China (960-1280) had a significant impact on commercial activity. These achievements contributed to the growth of trade and the development of large manufacturing industries, which produced consumer goods for a wide market. The expansion of agriculture and the availability of surplus food also opened up new opportunities for ordinary people to rise in society.