Make a judgment about why emergent requirements present a challenge to conventional software engineering approaches.

What will be an ideal response?

The vast majority of software developed to date assumes that the boundary between the software-based system and its external environment is stable. The boundary may change, but it will do so in a controlled manner, allowing the software to be adapted as part of a regular software maintenance cycle. This assumption is beginning to change. Open-world software demands that software "adapt and react to changes dynamically, even if they're unanticipated." By their nature, emergent requirements lead to change. How do we control the evolution of a widely used application or system over its lifetime, and what effect does this have on the way we design software? As the number of changes grows, the likelihood of unintended side effects also grows. This should be a cause for concern as complex systems with emergent requirements become the norm. The software engineering community must develop methods that help software teams predict the impact of change across an entire system, thereby mitigating unintended side effects. Today, our ability to accomplish this is severely limited.