What is considered to be america’s first big business that with the development of other industries

railroads were the first big business in america that helped with the development of other industries.

Explanation:

Using railroads and trains, other goods were transported from place to place, giving other industries the supply's they needed to grow!

Railroads

Explanation:

Right after  the decadesthat  followed the Civil War, the United States brilliant emerged as an industrial giant full of energy and space to grow to all directions , specially to the country side. Old industries expanded, changed some business and got many new ones, It refers to petroleum drilling, steel manufacturing, and electrical power, rubber exploration and others emerged. Railroads expanded significantly, bringing even remote parts of the country into a national market economy. With those railroads the country was literally united and walking as a unique body, growing as fast as they could, expending and making the country what it is today.

4 copper and gold, the california gold rush is why im pretty sure.