Answer:
I would say the melting pot
Explanation:
Gun powder was used for military purposes in the 919 A.D. It killed many people in China. It was explosive.
Answer: The optimum tariff.
Explanation:
The optimum tariff maximizes the liquid benefit resulted by the improve of the nation’s terms of trade, althought the volume reduction of trades.
In one side, the terms of trade of the country who imposes the tariff improve. On the other side, those of the trade partner decrease.
It should be noted that even that the terms of trade of the country that impose the tariff improved, those are smaller if compared to the losses of the trade partner