Final answer:
A surplus of food was the primary necessity for the growth of early civilizations, leading to settled populations, specialization of labor, and the development of complex societies.
Step-by-step explanation:
The first thing that civilizations needed to grow was a surplus of food. This food surplus allowed for the development of stable, settled populations and the rise of early civilizations. As a result, societies were able to support specialization of labor, leading to diverse professional roles such as farmers, weavers, artisans, and priests. These specialized roles contributed to the development of trade systems, in which goods and services were exchanged to meet a community's varied needs.
Consequently, the economy of these growing societies became more complex, making room for advancements in agriculture, large-scale architecture, writing, and the establishment of social classes. Without a surplus of food, made possible by advancements in agriculture, none of the other aspects of civilization, such as writing, organized religion, or a diverse labor force, could have been sustained.