Which of the following contributed to the increased economic and military power of the Sumerians?

Cause Effect increased economic and military power

a standing army of many trained soldiers

the formation of alliances with other city-states

a series of highly strategic army leaders

the development of bronze to make weapons

a standing army of many trained soldiers, the formation of alliances with other city-states, and the development of bronze to make weapons all contributed to the increased economic and military power of the Sumerians.