Maybe so you don't offend anyone?
The vice president has to act as the officer of the senate.
He/she must be familiar with all the presidents priorities and duties so that if anything happens, he/she is able to take on the roll of president. They also are an "assistant" for the president, and helps with making decisions for the country.
The correct answer is It allowed steel to be produced at a reasonable cost.
Explanation: Bessemer process, invented in 1856.
Bessemer has designed a shape with said receptacle for converting iron that can be heated when oxygen can be blown through the molten metal. With oxygen passed through the molten metal, which would react with carbon, releasing carbon dioxide and producing a purer iron / steel.
The process was quick and cheap, removing carbon and silicon from iron in a matter of minutes, but it suffered from being very successful. Excess carbon was removed and too much oxygen remained in the final product.
It kept the number of slave and free states even