Server Name: yang2336.soisweb.uwm.edu
Request Method: GET
Predefined variables are global variables in PHP that are already built into the language. They are automatically populated by the server and provide information about the server environment or the user's request. For example, `$_SERVER` is a predefined variable that contains server-related information, like the server name and the request method. These variables can help developers handle dynamic server-side functionality.