Why was gold used as medium of exchange?

Why do countries import and export products? Which component is considered a steady income while planning for savings in your personal budget? What is a society in which people have specialized jobs and must exchange goods and services they produce for goods and services produced by other people? Who was the main proponent of laissez-faire economics during the Enlightenment period? How much would one dollar in 1949 be worth today? Who makes economic decisions in North Korea? Why the aggregate supply curve has its particular shape? What can households do with their personal disposable income? How did farmer pay for the use of land they farmed? What is an advantage of demand priority? How did hideki help the economy? What questions must be asked about the use of resources in an economic system? What is the currency called in Uruguay? While researching a history paper you see a graph that shows federal spending on defense in the past 200 years. You notice that federal spending throughout the late 1900s shows much more spending on? How much does a beekeeper get paid each week? How did bonanza farms make it difficult for small farmers to complete in the late 19th centery? Could a future advance in technology allow production beyond the production possibility curve? What year did the song watermelon crawl come out? What effect would a decrease in production costs for all firms have on the aggregate supply curve? Why services are excluded from the measure of wealth?