4) Some of the adaptive approaches to developing systems (like agile) are becoming more popular. Are they better or more appropriate than prescriptive approaches in most cases? Why or why not?

Well, it is depend; some customers they might find that the adaptive approaches (like Agile) suit their needs, with non-observance of quality. Example of the phone or Tablet Apps, in few days you find a new app come out and probably after a few days, also you might get tired of it, or deleted it. At the other hand I think the prescriptive approach will last long, because of the effort and concentration put in to the project in order to be efficient even though the cost and time spent to accomplish it is most the time is too high.