In general they're part of the URL and that means they're part of what says what content the server should put on the page. So if you leave them out you could get different content or an error.

However in this case I suspect they're just tracking codes indicating which user you are and what page you came from etc. You can try removing them and seeing if you get the same content.

Often it's fairly obvious, at least with traditional web pages, which parameters are relevant and which are just session tracking info. You can strip most of it from Amazon URLs or eBay URLs for example and just keep the item number. But there's no single standard for how they get used by the server and more modern sites do complicated things with both the query string and the anchor.