Which diagram is used to visually represent the hierarchy of requirements?

The Requirements Hierarchy Diagram is specifically designed to visually represent the hierarchy of requirements within a project. This diagram illustrates how various requirements relate to one another, often categorizing them into different levels such as high-level requirements, sub-requirements, and detailed specifications. This hierarchical representation helps stakeholders understand the structure and organization of requirements, enabling better analysis, traceability, and prioritization.

In contrast, a Process Flow Diagram focuses on the steps and sequences involved in a process, illustrating how processes interact but not organizing requirements. A Use Case Diagram conveys the interactions between users and the system, showcasing functionalities rather than detailing requirements in a hierarchical manner. Meanwhile, a Data Flow Diagram depicts the flow of information through a system, emphasizing data inputs, outputs, and storage rather than categorizing requirements. Thus, the Requirements Hierarchy Diagram stands out as the appropriate choice for visually representing the framework of project requirements.