1.discovery of iron
2.the use of iron weapons
1.After the fall of the Han Dynasty..rebel groups seized control of their own areas of China.Their leaders made themselves kings and started fighting with each other.
2. The Sui Dynasty began to set in motion an artistic and cultural renaissance. Sui emperor seized the throne and took firm control of North China.
3. Sui emperor won the West and South and ruled over unified China..
4. Confucian rituals were reestablished. Penal code was set up and administrative laws that were lenient, fairer, and simpler.
5. Short regime collapsed in a welter of rebellions. The relations with the Turks in the West deteriorated and the wars in Korea to exact tribune failed,
Answer c. they believed gods controlled weather and climate
