When defining system interfaces, which statement is true?

When defining system interfaces, it is true that interface changes can affect the system. This is because interfaces serve as critical points of interaction between different components or systems, and any alterations to these interfaces can lead to unexpected behavior or failures in communication between those components.

For instance, if an interface specification is modified — whether it's the format of data being exchanged, the protocols used, or the methods of interaction — dependent systems must adapt accordingly. Failure to do so can result in integration issues, where one part of the system cannot properly communicate or process information with another. Therefore, it is essential to manage and clearly define interfaces to maintain system stability and interoperability.

In contrast, the other statements do not accurately reflect the importance or prevalence of interfaces. They either downplay the significance of these interfaces or overly narrow the scope of what should be defined. Recognizing the holistic nature of system interfaces and their potential impact on the entire system is crucial in requirements engineering and system design.