Which of the following statements are TRUE?

I. The context diagram should depict the system as a single bubble. II. External entities should be identified clearly at all levels of DFDs. III. Control information should not be represented in a DFD. IV. A data store can be connected either to another data store or to an external entity.

In Data Flow Diagrams (DFDs), Statement I is true because a context diagram represents the entire system as a single process bubble with external entities around it. Statement III is true because DFDs are designed to show only data flow and transformations, not control information like loops or decisions - those belong in flowcharts. Statement II is false because external entities should only appear in the context diagram and Level 1 DFD, not at all levels. Statement IV is false because data stores can only connect to processes, not directly to other data stores or external entities.