Since then the Great Wall was built, rebuilt to protect the northern borders of the Chinese Empire from the Hun's and Mongolian attacks during the rule of successive dynasties.
It's the farming of aquatic species such as fish, crustaceans, molluscs and aquatic plants! hope his helps
Answer:
That year was the same year as the end of the Roman Empire
Explanation:
Some problems faced were fighting against communism and keeping their democratic governments
they were also in huge amounts of debt