4. The insights of Solow and Romer can be combined in a single model of economic growth. Mathematically, the combination is relatively straightforward. Intuitively, all the results we have learned from both models continue to hold in the combined model. a. (4 pts) What is the principle of transition dynamics in the combined Solow-Romer model? b. (4 pts) Growth in the combined Solow-Romer is faster than the growth in the Romer model. Compare growth rates for Romer and Solow-Romer Models. c. (4 pts) We use growth models like the combined Solow-Romer model for growth accounting. Why is the growth accounting useful? (Hint: Reference article read during class)