Why is iron and steel industry called the basic industry?

The iron and steel Industry is the basic industry because:i. All the other industries - heavy, medium and light, depend on it for their machinery.ii. Steel is needed to manufacture a variety of engineering goods, construction material, defence, medical, telephonic, scientific equipment and a variety of consumer goods.iii. Iron and steel are heavy industries because all the raw materials, as well as finished goods are heavy and bulky. It involves heavy transportation costs.