Answer: The river valleys (the Nile,Tigris,and Eupharites valleys) provision of aquatic bodies enabled fishing, hunting.The constant flooding of these valleys provided natural irrigation, which made the soil to be fertile for crop production.
These civilization aids agricultural growth, and with continuous practices resulted in the emergence of social organization that promoted the formation of large group in the society, which necessitated the introduction of a sophisticated mode of administration for organization.
The improvements and expansion in agricultural growth leads to the establishments of well organised Complex society of villages ,towns, cities.
Finally specialize Labours to manage the agricultural growth and developments leads to the formation of distinct social classes which resulting in different innovations.