Which of the following was a Northern advantage at the beginning of the Civil War?

Northern Advantages Begin to Erode the Confederate Defense. The fiasco of First Bull Run in 1861 represented the first major shift in military policy. The war would not be over within a few months and Southern soldiers demonstrated their skills and determination.

Explanation:

you don't have the 'which of the following' part of your question but I hope this helps.

answer; (d) i believe that the correct answer is americans finally ran out of ammunition;

these civilizations were located around fertile rivers, where they could produce an abundance of crops