Real exports of goods and services increased 6 percent in the second quarter of 2021, compared with a decrease of 2.9 percent in the first quarter of 2021. Real imports of goods and services increased 7.8 percent in the second quarter of 2021, and by 9.8 percent in the first quarter of 2021.

a. Explain how the changes in exports and imports reported here influence the quantity of real GDP demanded and aggregate demand.

b. In which of the two quarters reported did exports and imports make the greater contribution to aggregate demand growth?