What is the key feature that distinguishes Agile from the Waterfall model?

The key feature that distinguishes Agile from the Waterfall model is that Agile iteratively delivers features via sprints. This iterative approach allows teams to develop software in small, manageable increments, ensuring that they can adapt to changes in requirements or feedback more effectively throughout the development process.

In Agile methodologies, the development is broken down into time-boxed iterations called sprints, which typically last from one to four weeks. At the end of each sprint, a potentially shippable product increment is delivered, enabling continuous improvement and adaptation. This is in stark contrast to the Waterfall model, where the project flows sequentially from one phase to the next without revisiting previous stages once they have been completed.

By focusing on delivering working software early and often, Agile allows for faster responses to user feedback and changing market needs. This flexibility is crucial for projects where requirements are likely to evolve, making Agile a preferred choice in dynamic environments. The other options associated with the Waterfall model—such as clear documentation, focus on budget and timeline, and final testing—do not reflect the core iterative and adaptive nature of Agile practices.