The answer is "The increasing expansion and centralization of state power".
Explanation:
Increased economic growth is an improvement throughout the economic cycle marked via an increase in output or jobs that cause consumers or companies to increase their revenue through their spending.
In such a global setting, centralization occurs whenever authority becomes shifted to a typically nation entity. In so far as an independent consumer's unit is typically thought of it as an individual citizen, authority is centralized in a larger unit, including the state or the local community.
The correct answer would be, "The growing feudal system prevented internal political conflict and stopped northern invaders from threatening China." The Zhou Dynasty began alongside the rise of the Iron Age, this immediately increased the power of the Zhou military.