Which feature helps to enhance a presentation's visual appeal through animation?

The feature that helps to enhance a presentation's visual appeal through animation is transitions. Transitions are effects that occur when you move from one slide to another in a presentation. They can create a smoother flow and add visual interest by changing how the slides appear on the screen, such as fading in, wiping, or flipping. These effects can draw attention to key points and maintain audience engagement.

On the other hand, design ideas focus primarily on the overall aesthetics and layout of the slides rather than animation, while the slide master is used for maintaining a consistent style across multiple slides. SmartArt is utilized to create visually compelling representations of information but does not provide animation options inherent to the transitions feature. Thus, in the context of enhancing visual appeal through animation specifically, transitions are the most relevant choice.