Ans: The use case may represent an important business process, which results in a higher importance level.The use case may support the generation of revenue or cost reduction. If so, this would result in a higher importance level.If the technology needed to support the use case is new or risky, that will result in a higher importance level.If the functionality in the use case is complex, risky, and/or time-critical, then the importance level will be higher.If the use case could help increase the level of understanding of the evolving design of the system, and this increase in understanding comes with little relative effort, then the importance level will be higher.Response: See pages 168-169