Which formatting change can effectively draw attention to key points?

Increasing the font size and changing the color is an effective way to draw attention to key points in a presentation. This approach leverages visual hierarchy, making important text stand out so that viewers can easily identify and focus on crucial information. Changing the font size enhances visibility, while selecting a contrasting color can create emphasis, potentially increasing engagement and retention among the audience.

Using a decorative border around text, while it may enhance the aesthetic appeal of a slide, does not directly enhance the visibility or importance of the content itself. Similarly, adding background music can be distracting rather than focusing the audience's attention on key points. A footer provides additional context or information but does not actively highlight or draw attention to specific content on the slide. Therefore, altering font size and color remains the most effective method for emphasizing key points in a presentation.