Final answer:
A project lifecycle defines the phases from project start to finish, with the spiral design process being a flexible and iterative model that allows for continuous improvement but may consume more time and resources.
Step-by-step explanation:
A project lifecycle defines the process or phases of a project from conception to completion. Different models explain the stages of project lifecycles, such as the traditional sequential process and the more flexible spiral design process. The sequential process follows a direct order from one step to the next, while the spiral design process involves iterative cycles, allowing for continuous refinement and evaluation of the project.
The spiral design process is advantageous because it often results in a more refined final product. However, it can also require more time and resources due to repeated cycles of evaluation and redesign. Planning for these iterations is crucial to avoid delays and budget overruns. Despite the possible disadvantages, the iterative nature of the spiral lifecycle aligns well with the dynamic requirements encountered in many projects.