There is a map showing Two Tang China from 618 AD to 907 AD. A map key indicates a black line or a green line represents a road, dark orange shading represents an area of high population density, and a white square indicates a metropolitan prefecture. The city of Duji is represented by many black and green lines, orange shading, and a white square. Changi an is represented by many black and green lines, orange shading, and a white square. Wuzhou is on the coast and is represented by many black and green lines and orange shading.

Based on the information in the map, which of these conclusions can be made?

Population density along the Huang He was greater than population density by the Yellow River.
Areas of high population density were well connected with extensive road systems.
Most people lived in rural areas without access to major cities.
Roads connected areas of high population density, and canals connected areas of low population density.

The conclusion that can be made based on the information in the map is:

- Areas of high population density were well connected with extensive road systems.