b) (i) In brief, explain the importance of R&D to economic growth (no need to provide a set of equations). (ii) Based on the Romer model, i.e model without capital, explain what would happen to the growth of technology if > 1 and = 1. (iii) Based on the Romer model, i.e model with capital and knowledge, explain what would happen to the growth of technology if + > 1 and + < 1