Final answer:
To display the duration of activities, bar graphs or Gantt charts are most suitable, whereas line graphs are better for illustrating relationships between two changing variables.
Step-by-step explanation:
For showing the duration of events or activities, a bar graph or a Gantt chart could be most effective. A bar graph uses bars to compare categories or show changes over time, and the length of the bar for each category represents the duration of an event or activity. On the other hand, a Gantt chart is specifically designed for tracking project schedules and is great for showing the start and end dates of the various elements of a project.
While line graphs are excellent for illustrating the relationship between two changing variables, such as the unemployment rate over time, they might not be the best choice for simply showing the duration of events. Line graphs are more suitable for displaying how one quantity changes in response to another and can show trends or patterns over extended periods.