What was an essential key factor in the development of civilization during this period?

An essential key factor in the development of civilization was the establishment of agriculture, which allowed societies to transition from nomadic lifestyles to settled communities. This shift enabled surplus food production, fostering population growth and the development of complex social structures. Additionally, the ability to cultivate land and domesticate animals led to advancements in technology, trade, and governance, laying the groundwork for the rise of cities and organized states.