What is the function of a span tag in HTML?

The span tag in HTML is an inline element that is primarily used to apply styles or manipulate specific portions of text within a block of content without altering the layout structure of the document. By using a span tag, you can target a word or phrase for formatting with CSS, such as changing its color, font weight, or applying other style attributes. This allows for precise control over the appearance of text without affecting the surrounding elements, making it a versatile tool for styling inline text.

The function of the span tag is distinct from the other choices. While defining a block of text, creating a new section within a document, or establishing a navigation area are all valid functions of different HTML tags, such as div, section, or nav, the span tag specifically focuses on inline text formatting. Thus, the choice emphasizing its role in formatting a word or phrase accurately reflects the span tag's purpose in HTML.