Breakdown of Google Adsense Code

Question

hello friends :)

i wan't to break down the google adsense code so i can understand what every element stands for.

<script type="text/javascript">
<!--

    google_ad_client = "pub-212231644091231233";

    /* 468x60, created 4/11/09 */

    google_ad_slot = "6006827265";

    google_ad_width = 468;
    google_ad_height = 60;

//-->

For example, if i want to dynamicly change the publisher id, do i have to change the ad slot number too?

What exactly, is the ad slot number?

Can i safely omit it?

Thank you very much.