Answer: Exchange
Explanation:
There are different currencies in the world used by different countries. We still need to trade with each other however so there must be a way for us to use our money to buy a good in a country with another currency.
We can do so by exchanging currency at a certain rate known as the exchange rate which is the rate that we can change a unit of one currency to another currency. This rate reflects the relative demand and supply factors of the various currencies such that one currency will be stronger or weaker than the other.