Which city became the steel and iron
capital of the U. S. by 1900?

Pittsburgh

Explanation:In 1900 the value of manufactured products in Pittsburgh was more than Cleveland and Detroit combined. How did Pittsburgh become the steel capital of the world? First there was iron. Pig iron is the product of the smelting process: the reduction of iron ore in a blast furnace.

the tariff was created to protect industry in the northern part of the united states. industries in the north were being driven out of business by imported goods that were priced at a low rate. the goal was to protect these industries   by taxing the goods.