Which was important to the industrial growth of America after the Civil War?

a. abundance of natural resources

b. immigration

c. a capitalist, free-enterprise (free-market) system

d. all of the above

D) All of the above was what was most important to the industrial growth of America after the Civil War. Being the huge country that the United States was, there was an abundance of natural resources due to the variety of different climates and immigration was plenty, as there were more opportunities in the United States than anywhere else. There has always been a capitalist, free-enterprise system in the US and this made it easier for people coming into the country to climb the social ladder.