【71-75】A requirement is simply a statement of what the system must do or what characteristics it needs to have. Requirements evolve from broad statements of overall （71） from the system to detailed statements of the business capabilities that a system should support to detailed technical statements of the way in which the capabilities will be implemented in the new system. （72） focus on describing how to create the software product that will be produced from the project Nonfunctional requirements are primarily used in the design phase when decisions are made about the user interface, the hardware and software, and the system's underlying architecture. The system's physical and technical environments would be considered （73）. The speed, capacity, and reliability of the system belong to （74）. （75） describes that who has authorized access to the system under what circumstances.
