How can the use of predefined variables like $_SERVER['DOCUMENT_ROOT'] improve the file inclusion process in PHP?

Using predefined variables like $_SERVER['DOCUMENT_ROOT'] can improve the file inclusion process in PHP by providing a reliable way to reference the root directory of the server. This helps ensure that included files are correctly located regardless of the file structure or server configuration. By using $_SERVER['DOCUMENT_ROOT'], the code becomes more portable and easier to maintain.

<?php
include $_SERVER['DOCUMENT_ROOT'] . '/path/to/your/file.php';
?>