The answer is, the different environmental secontions traded with each other.
They create platforms to plan things out hope this helped
Answer:
The Government of Japan is a constitutional monarchy in which the power of the Emperor is limited and is relegated primarily to ceremonial duties. As in many other states, the Government is divided into three branches: the Legislative branch, the Executive branch, and the Judicial branch.
Hope that helped :)
For one thing the Huns did not conquer the Roman Empire.