Final answer:
The era in question is characterized by the emergence of the Iron Age, the development of first states, and the appearance of written records from ancient civilizations. It featured significant developments in China where small kingdoms united under powerful dynasties like the Qin, leading to advancements in irrigation, metallurgy, philosophy, and technology.
Step-by-step explanation:
The period characterized by increasing social inequality and the establishment of first states, coinciding with the beginning of the Iron Age and the advent of written records from Chinese, Greeks, and Persians about Central Asia, marks a significant era in human history. This era witnessed the re-establishment of trade routes, the rise of Middle Eastern politics, and the formation of the largest empires till that time. Specifically, in China, around 2000 BCE, a population based on irrigated rice agriculture led to the growth of several small kingdoms that eventually united under a series of dynasties, starting with the Qin Dynasty in 221 BCE, marking the start of a remarkable period of Chinese imperial history. These early Chinese empires initiated major projects such as the construction of the Long Walls and the Grand Canal and maintained a monopoly on silk production, while leading the world in iron, copper, and porcelain production. The intellectual climate of the Warring States period led to the establishment of various schools of thought, including Confucianism, Legalism, and Daoism, providing the world with remarkable philosophical and technological advancements.