The currency can be exchanged for more of a foreign currency.
To cause no war on japan.
B. Flooding from monsoons
The Farming of plants was a turning point in human history. Ths allowed larger civiliations and the first empires to emerge. Also, technical advances were possible because people could specialize in one subject, such as mathmatics, due to calorie surplus, a.k.a farmers making more foo than they need for themselves.
