Which element attaches to an action to represent input or output?

Which element attaches to an action to represent input or output?

• A. Pin
• B. Object node
• C. Activity parameter
• D. Control node

Answer: (A)

In UML activity diagrams, an action uses pins to model the data that goes into and comes out of that action. Pins attach directly to the action and hold the input values before the action runs and the output values after it completes. You can think of pins as the data ports for that specific action, with tokens flowing through them as the activity executes. Object nodes, by contrast, are places where objects reside during the activity, not the direct input/output ports of a single action. Activity parameters connect data to or from the entire activity, not to an individual action. Control nodes handle the flow of control (like decisions, forks, or joins), not the data tokens.

In UML activity diagrams, an action uses pins to model the data that goes into and comes out of that action. Pins attach directly to the action and hold the input values before the action runs and the output values after it completes. You can think of pins as the data ports for that specific action, with tokens flowing through them as the activity executes.

Object nodes, by contrast, are places where objects reside during the activity, not the direct input/output ports of a single action. Activity parameters connect data to or from the entire activity, not to an individual action. Control nodes handle the flow of control (like decisions, forks, or joins), not the data tokens.