Which markup language is primarily used for creating the structure of web pages?

HTML, or HyperText Markup Language, is the primary language utilized for building the structure and content of web pages. It provides the foundational elements like headings, paragraphs, links, images, and other components that are essential for rendering a web page. By using various HTML tags, developers can define the layout and ensure that the browser can interpret and display the content correctly.

CSS (Cascading Style Sheets) is not used for structure; its primary role is to style the HTML elements, controlling layout, color, fonts, and responsiveness of the design. JavaScript, while integral to web development, focuses on adding interactivity and dynamic behavior to web pages rather than structuring them. XML (eXtensible Markup Language) is primarily used for data storage and transport, not specifically for web page structure, although it can also serve as a markup language. Thus, HTML stands out as the essential language for structuring web content.