What aspect does "tracking" specifically affect in typography?

The correct aspect affected by "tracking" in typography is the overall density of text. Tracking refers to the uniform adjustment of spacing across a range of characters in a word or line of text. By increasing or decreasing tracking, a designer can control how tightly or loosely the letters fit together, which influences the visual density of the text block. When tracking is adjusted, it affects the appearance of the entire text, making it appear more open and airy or more condensed and dense, depending on the adjustments made.

This control over overall text density can enhance readability, influence the aesthetics of designs, and establish a specific visual hierarchy within the layout. Proper tracking can improve legibility when dealing with various display sizes or at different viewing distances, making it a crucial concept in typography.