The story is: I'm trying Linux for the first time in my life. I'm encountering problems and I need to know what of them are responsibility of who. some of them are particular applications bugs, for example the calculator says 1+1=0 (I know that's very absurd, is a exaggeration to make the point). Others seem to be deeper and to have to do the system, but I can't separate the Desktop environment, Gnome in my case, from the Linux OS, such as Ubuntu or Mint. Can you tell me exactly what tasks the Desktop environments do in Linux?
If more appropriate, you can move my question to Unix and Linux.
IMPORTANT EDIT: THIS QUESTION SHOULD TOTALLY BE DELETED TO CLEAN, it is VERY unuseful now for me or for everyone, I needed to resolve a doubt and the answer I accepted it's very not-useful for everyone who reads it. I haven't deleted because doing so, according to the site, will affect me negatively in regards of being able to ask questions, because I will be deleting an question who has already an accepted answer.