How can the issue of session variables not persisting across pages be resolved in PHP?

The issue of session variables not persisting across pages in PHP can be resolved by ensuring that session_start() is called on every page where session variables are needed. This function initializes a session or resumes the current one based on a session identifier passed via a GET or POST request, or passed via a cookie.

<?php
session_start();

// Set session variables
$_SESSION['variable_name'] = 'value';

// Access session variables
echo $_SESSION['variable_name'];
?>