The answer to this question is tension
In 1787, delegates met in PA. They came from all of the 13 states except Rhode Island~
Answer:
Railroads used the iron to build railroad tracks but iron was weak and also dangerous. Soon people then realized that steel was a better material for tracks because it was able to hold more weight which then allowed heavier cargo. Railroads also transported mineral needed to forge steel.
Explanation:
The correct answer to this open question is the following.
The geographic feature of Mesopotamia that led to the Sumerians being easily taken over was the Tigris and Euphrates Rivers that made it easy for their enemies to navigate and invade them.
Sumeria was the oldest civilization known to man. Sumerians settled in the middle of the Tigris and Euphrates Rivers in the Middle East region. There, they developed agriculture techniques and learn how to use the flood of the rivers to grow crops in that fertile soil. That is how they prosper for some time until their enemies could access their city-states navigating through both rivers.