5. (Economic Fluctuations) Why doesn’t the National Bureau of Economic Research identify the turning points in economic activity until months after they occur?15. (Aggregate Demand and Supply) Determine whether each of the following would cause a shift of the aggregate demande curve, a shift of teh aggregate supply curve, neither, or both. Which curve shifts, and in which direction? What happens to aggregate output and the price level in each case?a. The price level changesb. Consumer confidence declinesc. The supply of resources increasesd. The wage rate increases12. (Convergence) Explain the convergence theory. Under what circumstances is convergence unlikely to occur?15. (Growth and the PPF) Use the production posibilities frontier (PPF) to demonstrate economic growth.a. With consumption goods on one axis and capital goods on the other, show how the combination of goods selected this period affects the PPF in the next period.b. Extend this comparison by choosing a different point on this period’s PPF and determining whether that combination leads to more or less growth over the next period.