⟩ Explain what does phase I and phase II mean?
The answer to this question depends on its context. If you are referring to the Software Development Life Cycle (SDLC), then the answer still depends on the model you are referring to. The number and nature of phases varies greatly between software development models. Generally, the phases of software development are:
Phase 1: Planning (a.k.a. the Requirements Phase)
Phase 2: Design
Phase 3: Implementation
Phase 4: Verification
Phase 5: Maintenance