Figure $2$: Level O DFD $($Note: Additional difficulty $-$ this diagram has some omissions and is incomplete; make reasonable assumptions where required$)$

$2.$ By using the provided level $0$ Data Flow Diagram $($DFD$)($Figure $2),$ complete the Event Table.

$3.$ Based on the diagram provided $($Figure $2)$ and the creation of the Event Table $($task $2),$ develop DFD fragments for the following use cases.

a$.$ View history

b$.$ Send message to physician

c$.$ Send message to patient

$4.$ Develop a complete ERD for the identified entities and relationships. The ERD must show correct cardinalities as well as entity attributes.

$5.$ Develop a Level $1$ Data Flow Diagram $($DFD$)$ for the case. Pick Level $0$ process of your choice for this purpose and try to come up with a reasonable refinement at Level $1.$