Answer:
I think any relationship between the Indus Valley and the deep Dravidian south is unlikely because of the vast gap in space and time. About 2,000 years and 2,000 miles. But linguistically, if the Indus script is understood, we may hopefully find that the proto-Dravidian roots of the Harappa language and South Indian Dravidian languages are similar.
B. Interchangeable parts were identical parts that could be exchanged for one another in the manufacture of guns, clocks, and other goods.
Slaves mainly but gold and salt good be included as well
Leepu & Pitbull join Hicham kaif in Katrina Kaif