Most HTML elements are a member of one or more content categories — these categories group elements that share common characteristics. This is a loose grouping (it doesn't actually create a relationship among elements of these categories), but they help define and describe the categories' shared behavior and their associated rules, especially when you come upon their intricate details. It's also possible for elements to not be a member of any of these categories....rest of the document, set up links to other documents, or convey...<head> , including the <title> , <link> , <script> , <style> , and...