Explain why the international trade requires a system for exchanging currencies between nations

Explanation:

Because if you produce goods in Japan then you use the yen as your currency (that is what you pay your taxes and workforce in). However you may sell your goods in the US and Europe. The people in the US will purchase them in dollars and in Europe in euros and you therefore need to convert these currencies into yen so that you can pay your local debts.

Internation trade requires a system because there many different trade laws in different countries and if there were different laws, the laws may "clash."

Explanation:

well considering i can't see the graph, it's probably prices

swahili is an extremely rich and complex civilization, a set of ethnic groups articulated by a language and a series of cultural elements that fuse the african traditions, islam and indian culture. this growth was largely a result of the indian ocean trading network that brought in not just man-made riches, but also religious ideas, specifically islam, which had a significant impact on the local culture. furthermore, the development of the swahili language gave a common cultural unity to the people.