Final answer:
A rise in input prices affecting many firms can shift the aggregate supply curve to the left, leading to stagflation, which is characterized by economic stagnation, high unemployment, and inflation.
Step-by-step explanation:
When a rise in input prices affects many or most firms across the economy, it can cause the aggregate supply curve to shift to the left. This shift represents a decrease in aggregate supply at every price level, which in turn increases the overall price level and can lead to stagflation, a condition characterized by slow growth (or recession), high unemployment, and high inflation. This was notably observed in the 1970s when increases in oil prices led to such economic conditions.