How did the economy of China change during the zhou empire?

Question

China's economy contracted as nomads from the north raided villages and threatened cities
China's economy expanded as Farmers using iron tools were able to grow more food
China's economy stalled as battles among warlords disrupted planting and destroyed crops
China's economy was threatened by Huang river floods resulting in widespread famine

Answer 1

China's economy expanded as Farmers using iron tools were able to grow more food