In this system of government states are largely independent but are loosely aligned with a weak central government. a
Unitary
b
Presidential
c
Parliamentary
d
Confederate
e
Federal

sumerians were polytheistic, meaning they believed in many different gods. so, the best answer is c.

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.