Final answer:
In data flow diagrams, the bubble symbol represents processes that transform incoming data flows into outgoing data flows.
Step-by-step explanation:
The symbol used in data flow diagrams (DFDs) to depict an entity or process within which incoming data flows are transformed into outgoing data flows is known as a c. bubble symbol. In the context of DFDs, these bubbles are used to represent processes, which are actions that convert input data into output data. The bubble symbols usually contain a descriptive title of the process being represented, and they are connected by arrows that describe the flow of data into and out of these processes.