The different aspects of a web page, such as heading levels, bold, italics, images, and paragraphs, are defined by HTML (HyperText Markup Language) and CSS (Cascading Style Sheets).

1. Heading Levels: These are defined by the `

` to `

` tags in HTML. The `

` tag represents the highest heading level, often used for the main title of the page, while `

` to `

` represent subheadings of decreasing importance.

2. Bold: Text can be made bold using the `` tag, which indicates that the text has strong importance, or the `` tag, which simply styles the text as bold without indicating importance in context.

3. Italics: Text can be italicized using the `` tag to emphasize the text (indicating importance) or the `` tag to style the text in italics without added meaning.

4. Images: Images are integrated into web pages using the `` tag, which requires the `src` attribute to specify the path to the image file, and often includes `alt` text for accessibility purposes.

5. Paragraphs: Paragraphs are defined using the `

` tag in HTML, which indicates a block of text that is treated as a distinct paragraph, usually with some margin for spacing.

These elements work together through HTML for structure and semantics, while