One advantage of city-states in mesopotamia was:
a. the creation of city-states led to the beginnings of the agricultural revolution.
b. urban centers were able to draw on the resources from their surrounding territories.
c. the people in mesopotamian city-states all traced their history back to a single ancestor, meaning there was great cultural unity in the region.
d. the city-states were larger political entities, which prevented war and conflict in ancient mesopotamia.

 The correct answer is :   A. The creation of city-states led to the beginnings of the Agricultural Revolution.

Explanation:  The first area that experienced a complete Agricultural Revolution was Southwest Asia since Mesopotamia. There were an extraordinary variety of wild plants and animals capable of domestication provided a rich array of species on which the now largely settled gathering and hunting people could draw. Mesopotamia was not only one of the first places to develop agriculture, but it was also at the crossroads of the Egyptian civilizations and the Indus Valley.

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.