The ________ model is preferred for software development when the requirements…

Answer: Evolutionary Model is preferred when requirements are not clear.

Why: Iterative development and prototyping let stakeholders see working increments early, reveal unstated needs, and allow requirements to be refined over multiple cycles.

• Build small increments or prototypes to explore requirements.

• Obtain stakeholder feedback and update requirements accordingly.

• Repeat cycles until requirements stabilize, then finalize the system.

When to use: The Evolutionary Model is best for projects with unclear, incomplete, or rapidly changing requirements, or when early user feedback is essential.

Why other models are less suitable:

• Rapid Application Development focuses on speed using prototyping and tools, but it assumes parts of the system can be rapidly built; it may not provide the same systematic requirement evolution as the Evolutionary Model.

• Rational Unified Process is an iterative framework but is more formal and heavyweight; it requires more upfront process definition.

• Waterfall Model is linear and assumes stable requirements, so it is unsuitable when requirements are unclear.

Practical steps in the Evolutionary approach:

1. Gather initial requirements and build a quick prototype.

2. Get stakeholder feedback and refine requirements.

3. Develop the next increment incorporating the refinements; repeat until stable.

4. Finalize and deliver the complete system.