Final answer:
In an Activity Diagram, the modeling element 'associations' is not used; it is more commonly associated with structural diagrams such as class diagrams.
Step-by-step explanation:
The modeling element not associated with Activity Diagrams is associations. The options given include swimlanes, associations, an initial node, final node, and fork and join nodes. Swimlanes are used to organize actions related to different objects or roles within an activity diagram. Initial nodes signify the start of the flow in an activity diagram, while final nodes indicate the end. Fork and join nodes are used to model parallel and concurrent flows in an activity diagram.
Associations, on the other hand, are more commonly associated with class diagrams or other structural diagrams to show the relationships between classes or objects, not the flow of activities.