The flat portion of the long-run average total cost curve is a result of:
a. economies of scale

Higher energy prices in the 1970s reduced labor productivity because

A. the rise in energy prices tended to push firms away from labor-intensive measures and toward more capital-intensive techniques. B. energy and capital are substitute inputs. C. a great deal of investment went into transforming the existing capital stock into more energy-efficient forms. D. labor productivity has been lower when used with more capital-intensive techniques.

A permanent reduction in international trade barriers would

A) decrease long-run aggregate supply. B) increase long-run aggregate supply. C) decrease aggregate demand. D) increase aggregate demand.