Final answer:
By 1000 BCE, the Chinese had transitioned from using bronze to using iron, signifying the arrival of the Iron Age, when smelting technology allowed for the widespread production of iron goods.
Step-by-step explanation:
By 1000 BCE, the Chinese had transitioned from using bronze to using iron. This transition is a significant event in history, marking the end of the Bronze Age and the beginning of the Iron Age. The critical technological factor in the intensifying warfare of the period from about 500 to 200 BC was iron due to its availability in the earth without the need for long-distance trade as bronze had. When the Bronze Age ended around 1100 BCE, some innovative smiths figured out how to forge iron implements, which were hard and durable. Consequently, around 1000 BCE, the technology for iron smelting had sufficiently developed, enabling societies to make tools, weapons, and good from this metal, effectively increasing both agricultural productivity and the armament of soldiers.