What were the problems and challenges people faced in ancient Mesopotamia and the Nile River Valley that led to the creation of civilizations?

The first
major issue people faced in these areas was the problem of how to sustain a food supply. The
neolithic transition, in which people settled down in one area to farm rather than moving as
hunter-gatherers, allowed for more efficient food production than had existed previously, but
the increased population density also required the ability to produce a steady food supply
within a limited area. In both regions, this required people to cooperate to develop irrigation
systems. 

The concentration of population in fixed settlements raises other
issues that would not have been problems in small bands of hunter-gatherers. One needs to
arrange for clean drinking water and disposal of human waste downstream of sources of drinking
water, for example. The use of fire for cooking and metallurgy in a settlement means one needs a
cooperative means of dealing with fires. As one no longer has the safety valve of forming a new
small band and moving away from conflicts, there needs to be some official conflict resolution
mechanism and various forms of laws about property. All these give rise to the need for many of
the mechanisms of government that we see developing in ancient Egypt and Mesopotamia, including
legal codes, taxation, and some form of government bureaucracy.