Metal made from iron, less brittle and easier to shape, created by blowing air into molten cast iron.

Metal made from iron, less brittle and easier to shape, created by blowing air into molten cast iron.

• A. Papermaking
• B. Chinese Compass
• C. Woodblock Printing
• D. Steel

Answer: (D)

Steel is an iron alloy that is tougher and more workable than plain iron or cast iron. The description points to steel because blowing air into molten cast iron introduces oxygen, helping remove impurities and adjust carbon content. This process lowers brittleness and increases malleability, letting the metal be shaped more easily and used for stronger tools and weapons. The other options—papermaking, a navigational instrument, and woodblock printing—are not about transforming iron into a metal with these improved properties, so they don’t fit the described production method.

Steel is an iron alloy that is tougher and more workable than plain iron or cast iron. The description points to steel because blowing air into molten cast iron introduces oxygen, helping remove impurities and adjust carbon content. This process lowers brittleness and increases malleability, letting the metal be shaped more easily and used for stronger tools and weapons. The other options—papermaking, a navigational instrument, and woodblock printing—are not about transforming iron into a metal with these improved properties, so they don’t fit the described production method.