Final answer:
The implementation phase involves building the model or product, while the maintenance phase focuses on ongoing support and updates to the software.
Step-by-step explanation:
The implementation phase and the maintenance phase are two distinct stages of the Software Development Life Cycle (SDLC).
The implementation phase is where the actual development takes place. It involves building the physical or virtual model, creating a prototype, or manufacturing the product. In this phase, the design is refined based on the constraints and criteria that have been met.
The maintenance phase comes after the implementation phase. It focuses on keeping the software running smoothly, fixing bugs, adding new features, and making updates as needed. It involves ongoing support and maintenance to ensure that the software is functioning effectively and meeting the users' needs.