What visual tool helps the project team understand the flow of activities?

A network diagram is the correct choice for understanding the flow of activities in a project. This visual tool outlines the sequence of tasks and showcases how different activities are interrelated, highlighting dependencies and the overall project structure. By providing a clear depiction of the project's critical path, the network diagram allows the project team to see how delays in one task can impact subsequent activities, facilitating better planning and management of the project timeline. This tool is particularly valuable for complex projects where understanding the relationship between tasks is crucial for successful execution.

On the other hand, a Gantt chart is primarily used for scheduling tasks over time, displaying start and finish dates but not emphasizing the dependencies between those tasks as effectively as a network diagram. A resource histogram provides a visual representation of resource allocation but does not illustrate the sequence of tasks. A bubble chart is not typically used in project management for activity flow but rather for visualizing relationships between variables.