Who produced large quantities of steel very efficiently by buying and controlling iron ore deposits, steel mills, and railroads?
a. andrew carnegie
b. jean lenoir
c. alexander graham bell
d. thomas edison

The correct option is:

A. Andrew Carnegie.

Andrew Carnegie (1835 - 1919) was a Scottish-American industrialist, business magnate, and philanthropist. He drove the development of the American steel industry in the late 19th century. By the 1860s he held investments in railroads, sleeping cars, bridges, and oil derricks. He built Pittsburgh's Carnegie Steel Company, and after selling it, he surpassed John D. Rockefeller as the richest American for a few years.

answer:

it caused mass african migration, african populations to grow, african empires to topple, and racism against slaves to emerge.