What are the two main models found in the Software Development Life Cycle (SDLC)?

The two main models in the Software Development Life Cycle (SDLC) encompass various approaches to project management and software development. The Waterfall method is a traditional, linear approach where each phase must be completed before the next one begins, making it straightforward and structured. This model emphasizes thorough documentation and defined stages, which can be advantageous for projects with well-understood requirements.

On the other hand, Agile methodology represents a more flexible and iterative approach, allowing for changes and improvements along the development process. It focuses on collaboration, customer feedback, and the delivery of functional increments of software—ensuring that the final product aligns more closely with user needs and expectations.

These two models—Waterfall and Agile—contrast in their approach to handling project requirements and changes, making them foundational in understanding SDLC. The prominence of both models in practice demonstrates their unique strengths in managing software development projects, catering to different types of projects and client needs. Other pairs of models mentioned in the options, while valid in their own right, do not encapsulate the primary structural methodologies as effectively as Waterfall and Agile.