Aggregate Demand and Aggregate Supply model I What are the three reasons the aggregate demand {AD} curye slopes downward? Explain them in detail. "A Change in aggregate demand [ADJ alter output in the short run but not in the long run." Do you agree with this statement? Explain your answer. "Unlike the shortrun aggregate supply curve, longrun aggregate supply curve is assumed to be constant {a yertical linei." Do you agree with the statement? Explain your answer. What determines the economy's supply of goods and services in the long run