Strategy in 21 century pharmaceutical industry: mark and Pfizer

You had to answer this 3 questions in one page : 1. Why was the pharmaceutical industry one of the most profitable industries in the world through the 1980s? 2. What have been the most important changes in the pharmaceutical industry's structure during the past two decades? What does each change imply for the strategy of an effective pharmaceutical firm? 3. How do you evaluate the strategies that Merck and Pfizer have pursued in light of the changing industry structure? What would you recommend to Richard Clark and Jeffrey Kindler as they become CEOs of Merck and Pfizer, respectively? thanks!