Multisite and plugins

Hi,

I have just been given a new WordPress site to work on and there is no option to add a plugin. I am wondering if the site is part of a multisite (i have not worked with multisite before). I only have login info for the one site and no ftp access yet. How do I tell if my site is a part of multisite. It seems to be missing a lot of the admin controls such as the ability to edit php files or even see their content.

Thanks
Janey