Question

why iron and steel industry referred to as the backbone of modern industry

Answer 1

iron and steel industry referred to as the backbone of modern industry because for making any industry we use iron and steel
and for making machine iron and steel are
also use

Answer 2

Answer:

Steel is called the backbone of the modern industry because almost everything we use is either made of steel or has been made with machinery or tool made out of steel. The steel industry is basically the feeder industry, whose products are the raw materials for other industries.