Final answer:
A video demonstrating the process is the most effective visual aid for teaching a puppy to walk on a leash.
Explanation:
The best visual aid for teaching a puppy to walk on a leash is a video
that shows the process in action, providing a clear demonstration for both the trainer and the puppy to learn from. This visual aid offers a dynamic representation of the training process, incorporating movement and real-time instruction into the learning experience.
In contrast, a chart, bar graph, or photo may not capture the dynamic nature of leash training as effectively as a video.
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