Which of the following is NOT a page element that can change in formatting?

The table of contents is a specific element that typically serves as a navigational tool in a document, providing an outline of the content and structure of the work. While the visual layout or styling of the table of contents can change (such as font size or color), the fundamental nature of how a table of contents functions remains consistent; it lists the sections or chapters along with their corresponding page numbers.

In contrast, main headings, subheadings, and paragraph formatting are core elements of text style and layout that can frequently change with different formatting options. For instance, main headings and subheadings can vary in terms of font, size, and color to denote hierarchy and importance, while paragraph formatting can include adjustments to line spacing, indentation, and alignment.

The table of contents is a structured listing that serves a specific function in guiding readers, distinguishing it from other text elements that are more fluid and subject to different formatting choices.