INDIAN HISTORY

Detailed explanation-1: -Iron was not known to the Harappan people. Since the civilization existed during the Bronze Age, it had made many metallurgical advances in copper and bronze but not in Iron.

Detailed explanation-2: -Steel was not invented at the time of Harappan civilization. Copper and bronze were the common metals used at that time, especially to make pots.

Detailed explanation-3: -The Harappan people knew the uses of Iron, Copper and Bronze .

Detailed explanation-4: -Iron was not used in the Harappan cities . They also used gold and silver in the form ornaments and coins.

Detailed explanation-5: -Detailed Solution. The correct answer is option 4 i.e Iron, The people of the Harappan sites (also known as the Indus valley) had the knowledge of using bronze, copper, silver, and gold but they did not use iron.