What did the northern states invent during the civil war?

a standing committee

explanation:

the industrial revolution pushed the world into modern industrialization. it changed the course of history profoundly. it caused rapid urbanization and pushed cities and countries into development. the industrial revolution began in great britain with a series with new inventions which led to the creation of machines and mass production.

this caused the country to gain wealth and money and become an international superpower. it improved transportation and manufacturing inside the country, pushed people to live in urban areas and britain to become the most powerful nation in the world for a while.

c. pro-democracy demonstrations.