What is a fork node?

What is a fork node?

• A. Marks the start of concurrent sequences in an activity
• B. Marks the end of alternative sequences in an activity
• C. Represents a single instance participating in an interaction
• D. Is used to merge parallel paths

Answer: (A)

A fork node is used to split one flow into multiple simultaneous flows in an activity diagram. When control reaches the fork, the single path diverges into two or more outgoing paths, allowing tasks to be performed in parallel. This parallelism is often followed later by a join node that brings the threads back together. Think of it like starting several tasks at the same time after a single trigger—one incoming edge feeds several outgoing edges, each path representing a concurrent sequence. The other options describe different concepts: ending alternative sequences is handled by a merge/join, representing the consolidation of different paths; a single instance in an interaction is unrelated to splitting flows; and merging parallel paths is the job of a join node, not a fork.

A fork node is used to split one flow into multiple simultaneous flows in an activity diagram. When control reaches the fork, the single path diverges into two or more outgoing paths, allowing tasks to be performed in parallel. This parallelism is often followed later by a join node that brings the threads back together.

Think of it like starting several tasks at the same time after a single trigger—one incoming edge feeds several outgoing edges, each path representing a concurrent sequence. The other options describe different concepts: ending alternative sequences is handled by a merge/join, representing the consolidation of different paths; a single instance in an interaction is unrelated to splitting flows; and merging parallel paths is the job of a join node, not a fork.