the gas is carbon-dioxide....
After nearly four centuries of internal divisions and strife, China was reunited under the leadership of Yang Jian. A member of a respected aristocratic family, Yang Jian founded the Sui Dynasty. Yang Jian used Buddhism to help unite the kingdom.
Answer:
the north got a lot more factories and started to produce a lot of goods that were needed all over.
2 i believe I am not 100% sure
