Answer:
The reason why we need a system of currency exchange in order to conduct international trade is because different countries use different types of currency. They do so because national sovereignty allows each nation to establish its own currency. However, we need a system to pay for goods that are purchased from other countries. This is why the currency exchange system allows us to conduct international trade
Explanation:
This answer depends greatly on the time period in question, but generally speaking it is true that the presence of many rivers and mountains protected China from invaders, and allowed their culture to grow with little outside influence, with the exception of Mongolian invasions from the north.
Answer:
Probably because of the great depression.
Explanation: