<span>Advances that were made during the Han Dynasty:
Predict eclipses of the sun
Doctor's created new medicines
Chinese language grew from 3000 to 9000 characters
Paper was invented
Wheelbarrows and fine vases and china
Seismograph</span>
They switched from kinship like tribes to social heirarchy w/ nobles.
The best answer is B) Difficulties in royal succession.
One issue that the Mongol Empire had was a lack of a system of orderly succession when a ruler's end came. Future Islamic Empires, influenced by the Mongol ruling traditions, often experienced similar problems.
