If you mean which species, it would be the Homo sapiens.
Do you mean corps or crops.?
The determination of the exchange rate is made through the currency market. The exchange rate as the price of a currency is established, as in any other market, by the meeting of supply and demand of currencies. If you analyze, for example, a hypothetical situation, in which there are only two currencies the euro and the dollar. The demand for dollars (supply of euros) arises when consumers in different European countries need dollars to buy goods from the United States. In the same way dollars are needed if a European company wants to buy a building in New York, when a German citizen travels as a tourist to San Francisco or if a Swedish company buys shares in a US entity, but there may still be an additional reason to demand dollars that is pure speculation, that is, the thought that the dollar will rise in value against the euro will cause the demand for dollars to rise.
If the opposite is analyzed, the supply of dollars (demand for euros), this is done by all those companies and citizens who need euros for their needs (basically the same ones that we have analyzed before, purchase of goods and services, investments and speculation. )
The balance in a competitive market between supply and demand will mark the price of the dollar against the euro or what is the same the price of the euro against the dollar. In currency markets depreciation is known as the decline in the price of one currency over another.
