The greatest single factor to spur the amazing industrialization of the post-civil war years was
a. mining
b. the railroad network
c. the steel industry
d. agriculture

b. The railroad network

Explanation:

The construction of the U.S. railroad network allowed a faster movement of raw materials and goods throughout the American territory. This promoted a faster capital growth rate, and when capital is abundant, industry ensues.

Mining, the steel industry and agriculture are only specific sectors that benefited from the construction of the U.S. railroad network. It was the railroad network that boosted growth.

id say bottom left to top top left to bottom right and middle to middle

explanation:

your answer will most likely be a.