What impact did improvements in transportation have on tang and song china?

could you use this to with a topic?

the key difference between a democracy and a republic lies in the limits placed on government by the law, which has implications for minority rights. both forms of government tend to use a representational system — i.e., citizens vote to elect politicians to represent their interests and form the government.

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers