1. Explain why the aggregate demand curve slopes down?2. An increase in the sale

1. Explain why the aggregate demand curve slopes down?2. An increase in the sale of new houses is often a sign that an economic expansion is coming. Why would this be the case?3. How is the U.S. national economy different from those of other nations?4. What impact did the Great depression have on the way government set policy?5. Why is it diffficult to test macroeconomic theories?Answers should be 75 words and at least use your textbook as source material. All sources must be referenced paraphrased andquoted material must have accompanying citations.