Final answer:
The requirements management plan is the document that details how project needs will be analyzed, documented, and managed throughout the life of a project.
Step-by-step explanation:
The document that outlines how project needs will be analyzed, documented, and managed is known as the requirements management plan. This plan is vital for ensuring that the project's requirements are comprehensively captured and well-managed throughout the project lifecycle. It typically includes processes for how requirements are identified, analyzed, documented, and changes are controlled. In contrast, a requirements traceability matrix is a tool used to ensure each requirement's origin is clearly documented and that it is tracked through the project lifecycle. The Work Breakdown Structure (WBS) is a deliverable-oriented breakdown of a project into smaller components. A project scope statement, on the other hand, defines the project scope and the work that is needed to complete the project, but it doesn't document the process of managing requirements.