A speaker wants to demonstrate the change in world population since 1840. His clearest and most effective option for a visual aid to demonstrate this is a(n)______

A. Line graph.
B. Map.
C. Bar graph.
D. Chart.

Which form of presentation aids are drawings that outline and explain the parts of an object, process, or phenomenon that cannot be readily seen.

A. graphs
B. diagrams
C. objects
D. charts

Be sure that all visuals you use in your presentation are

A. complex
B. simple
C. brightly colored
D. more interesting than what you are saying

Speaking effectively also involves writing and using effective presentation slides.

A. 对
B. 错

List and explain two considerations when using color in your slides.