Which type of flow indicates the sequence of activities in BPMN?

The sequence flow is the primary mechanism in BPMN (Business Process Model and Notation) used to indicate the order in which activities occur in a process. It is represented by a solid line with an arrowhead, demonstrating the flow of control from one activity or event to another. This is crucial for modeling processes because it clearly defines the progression from one step to the next, allowing anyone reviewing the model to understand how tasks are coordinated and the pathway through the process.

While message flow, conditional flow, and other types of flows have their own specific uses within BPMN, they do not serve the same purpose as sequence flow. Message flow is used to illustrate communication between different participants or entities within a business process. Conditional flow could suggest paths taken based on certain conditions being met, which introduces decision-making into the process rather than simply illustrating the order of operations. Pi flow is not a standard term in BPMN and often does not apply to BPMN notation. Thus, the sequence flow remains the essential element for depicting the sequence of activities in a BPMN diagram.