I am writing a report and I have stumbled across a topic I am not quite sure how to to discuss. Essentially I have been doing a little research on the Unity shell system and its usage in Ubuntu primarily. I understand that Unity is a shell interface and that it runs with GNOME desktop environment. My question is in a broad description how does it do this is the shell interface simply how the user triggers certain programs to do certain tasks within the GNOME desktop environment? My questions stems from the fact that everywhere I have researched seems to compare GNOME and Unity yet how I understand it they serve different processes almost entirely. Am I missing something?
Part of your confusion may be from the fact that GNOME has two parts, the shell (which is comparable to Unity), and the desktop environment (which Ubuntu uses with Unity).
Unity and the GNOME Shell are interfaces. The GNOME wiki explains it like this:
GNOME Shell provides core interface functions like switching windows, launching applications or see your notifications.
They are both just interfaces to control your applications and settings.
The GNOME desktop environment is (basically) a collection of applications. In addition to the specialized programs featured here, it also includes common applications like the file browser (Nautilus), terminal (GNOME Terminal), and others.