Brief explanation of all elements in activity diagrams. | UML Interview Questions

=> Activities: An activity indicates an action that performed in the system.
=> Transitions: Transitions are represented by open arrow heads. Transitions are used to indicate the flow among elements in the diagram.
=> Decision Points: The logical branching is depicted by the decision points.
=> States: A state is shown in a rounded rectangle. States are indicated to mention the mile stones of processing in the activity diagrams.