Final answer:
Regions to the north of China posed a greater threat due to their nomadic, militaristic nature and the absence of natural barriers, leading to frequent invasions and the rise of dynasties like the Yuan and Qing.
Step-by-step explanation:
The Northern Asian regions and peoples traditionally posed a greater threat to China than the Southern regions because of the different nature of their interactions and the geographical advantages they held. The overland system managed China's relations to the north and west with nomadic tribes, such as the Xiongnu and the Mongols, who, despite their economic and technological backwardness, had access to advanced military technology like horses and archery. The flat terrain and lack of natural barriers made it easy for these nomadic tribes to conduct raids against Chinese farming communities, sometimes even reaching the capital. This continuous threat eventually led to invasions and the establishment of dynasties by these tribes, specifically the Yuan and Qing dynasties.
In contrast, the Southern regions were separated by natural barriers such as the Himalayas, which proved to be a formidable defense against invasions. Hence, China's relations with the East and South, including trade and tribute systems, were more manageable, focusing on diplomacy and cultural exchanges rather than military threats. The geography not only offered protection but also shaped a different cultural and political landscape, as southern dynasties developed with lower degrees of centralized control and focused more on trade and agriculture.