What happened to the world economyWhat was the challenge to economists posed by "stagflation"? Group of answer choices how to control runaway spending how to better regulate credit and borrowing how to simultaneously control inflation and unemployment how to increase wages and productivityin 1971? Group of answer choices There was a worldwide economic boom due to the discovery of new oil reserves in Africa. The U.S. no longer based the value of the dollar on gold so the exchange rate of the world's currencies began fluctuating. The Japanese yen replaced the dollar as the world's reserve currency. The U.S. stopped exporting goods to other countries