Give reason —

1. The iron and steel industry forms the backbone of Indian economy.
2. Traditional raw material have been replaced by petrochemical products.

1. The iron and steel industry forms the backbone of Indian economy as it provides raw material for all other industries like automobiles, locomotives, rail tracks, ship-building, machine and tools, and manufacture of defence equipment, etc.
2. Traditional raw material have been replaced by petrochemical products because:
   1. petrochemical are cost-effective.
   2. economically stable
   3. cheaper as produced at mass scale
   4. raw material is easily available
   5. not dependent on agricultural raw material.