Which of the following accurately describes a DFD?

A Data Flow Diagram (DFD) is a graphical representation that illustrates how data moves through a system. It focuses on the flow of information, showing the relationship between different processes, data stores, and external entities. By doing this, it helps in understanding the system's operations while depicting the inputs and outputs associated with various functions.

The description that a DFD shows how data flows between processes is accurate because the primary purpose of a DFD is to detail the movement of data, highlighting how information is transformed by each process and where it is stored or consumed. This makes it a vital tool for analyzing and designing systems, ensuring that data management is clearly understood and documented.

In contrast, the other options do not capture the essence of what a DFD is. For instance, solely focusing on user interfaces pertains to user experience design rather than data flow representation. Similarly, modeling database relationships exclusively ignores the broader scope of data interactions and processes represented in a DFD. Lastly, limiting it to project management tasks overlooks its primary function of representing data flow in various types of systems, whether in projects or ongoing operational environments.