chcę użyć funkcji bcc lub cc w tej funkcji poczty?

Tutaj Moja funkcja poczty

 <?php
//SENDS EMAIL THAT TELLS THE USER TO ACTIVATE THE ACCOUNT
$activation = 'activation.php?key='.$key;
$your_email = '[email protected]'; //CHANGE TO YOUR SETTINGS
$domain = $_SERVER["HTTP_HOST"]; //YOUR DOMAIN AND EXTENSION
$to  = $email;
$subject = 'MyDomain Activate Account';
$message .='<img src="http://mydomain.com/images/securedownload.jpg"/>';
$message = 'Welcome,<br/> '.$_POST['username'].'. You must activate your account via   this       message to log in. Click the following link to do so:   http://'.$domain.'/'.$activation;
$headers = 'From: Mydomain<'.$your_email.'@'.$domain.'>\r\n'; //MODIFY TO YOUR SETTINGS
$headers .= 'Content-type: text/html\r\n';
mail($to, $subject, $message,  $headers);
?>