What does a Package Diagram show regarding model elements?

A Package Diagram illustrates the hierarchical organization of model elements and how they relate to one another in terms of dependencies. It represents how various packages (which can be collections of classes, interfaces, or other elements) are structured and how they depend on each other. This is essential in understanding the architecture of a system, as it helps to visualize how different components are grouped and how they interact.

In a Package Diagram, packages can show both the contents (the model elements contained within them) and the relationships between these packages, such as dependencies indicating that one package relies on another. This helps modelers effectively manage complexity in large systems by breaking down the system into manageable pieces and highlighting the dependencies that need to be understood when working with those pieces.

While other options reference important concepts in system modeling, they do not align with the primary focus of a Package Diagram, which is fundamentally about organizing and depicting relationships between components rather than the specifics of workflows or data handling.