Which of the following statements about a data flow diagram is true?

A data flow diagram (DFD) is a graphical representation of the flow of data within a system, illustrating how data moves between processes, stores, and external entities. In this context, a spontaneous generation process is defined as a process that initiates its output without any input. This aligns with the nature of such processes, which, by their definition, generate outputs independently and therefore do not require any incoming data flow.

The concept of spontaneous generation is important to understand because it emphasizes that not every process in a system is dependent on an incoming flow of data or resources. In practical applications, this can represent processes that trigger actions or outputs based on pre-defined conditions, timers, or other system events.

The other statements present inaccuracies according to the rules governing DFD representation. For example, a process typically is expected to have incoming data flows in order to perform its function effectively, rather than having none at all. Thus, this aspect of DFDs helps to clarify boundaries between what constitutes valid processes in the diagram while reinforcing the idea that spontaneous processes are unique in that they do not conform to the conventional flow requirements.