What are PHP superglobals? Provide examples of at least three superglobals and explain their uses.

Superglobals are built-in variables that are always accessible, regardless of scope. Three examples are:

• $_GET: Used to collect form data after submitting an HTML form with the method="get".
• $_POST: Used to collect form data after submitting an HTML form with the method="post".
• $_SESSION: Used to store session variables across multiple pages.