2a. What assumptions cause the immediate-short-run aggregate supply curve to be horizontal? Why is the long-run aggregate supply curve vertical? Explain the shape of the short-run aggregate supply curve. Why is the short-run aggregate supply curve relatively flat to the left of the full-employment output and relatively steep to the right?

3a. Why does a reduction in aggregate demand in the actual economy reduce real output, rather than the price level? Why might a full-strength multiplier apply to a decrease in aggregate demand?