In which phase would defects be identified and fixed?

The testing phase is where defects are systematically identified and addressed. During this critical period, various testing methodologies, such as unit testing, integration testing, system testing, and acceptance testing, are employed to evaluate the system thoroughly against the specified requirements. This is the stage where developers and testers work together to uncover bugs or issues that could affect functionality, performance, or user experience.

As the software is executed in a controlled environment, any deviations from expected behavior are logged as defects, which can then be prioritized and fixed before the final release. This proactive approach helps ensure that the product is delivered with a higher quality and minimizes potential problems for end-users.

In contrast, the implementation phase primarily involves deploying the software into a production environment and might include some initial troubleshooting, while the maintenance phase focuses on ongoing support and updates after release. The design phase focuses on planning and architecture, and typically doesn't involve defect identification in a deployed system. Thus, the testing phase is uniquely positioned as the appropriate time for pinpointing and resolving defects effectively.