Different Linux distributions can use different GUI's some will use Gnome or KDE. Most distributions will let you choose which you want. If you have an older machine you might want to use XFCE or LXDE window managers. If you are looking for a distribution you might want to try Linux Mint it uses all of these Window Managers.
no
The GUI uses unnecessary resources.
Yes and no. Yes, Linux has a GUI. Dozens, in fact, all running on the X Windowing System. No, Linux is not BASED on a GUI. Only Windows really has the concept of an operating system "based" on a GUI. To Linux, the X Windowing System and whatever you run on top of it is just another application.
i assume by gui, i assume you mean the window manager. gnome and kde are popular. i personally like to use xfce, the "cholesterol free desktop environment".
Not sure what your question is asking, other than the GUI is displayed by the desktop manager.
There are many differences between the Graphical User Interfaces of Windows and Linux. There are similarities as well. To be exact, Linux, itself has no GUI per se. The GUI(s) that you can use, and there are literally hundreds to choose from, are separate programs running under Linux. [speaking simply here]Linux itself is the core (kernel) of the Operating System, whereas the GUI, the file managers, web browsers, chat programs etc, are all applications that give the OS "features". With Windows you only have the included GUI, that is unless you install a modification such as WindowBlinds(TM). Linux, and many other POSIX compliant OS's can use many GUI, here is a brief listing and some links to GUI sites. KDE - The K Desktop Environment: http://kde.org/Gnome (Pronounced with a hard "Guh" as in Guh-Nome: http://gnome.org/Enlightenment: http://www.enlightenment.org/blackbox: http://sourceforge.net/projects/blackboxwmAfterStep: http://freshmeat.net/projects/afterstep/ and many more...
The Linux kernel itself does not include a GUI. However, most Linux distributions have one. Yes, Linux have a GUI.Today many kind of vendor available in Linux Like Redhat fedora,Ubuntu,Suse, Mandriva and many more. Those Linux version provide Cmd and GUI mode for work.
Windows has a GUI and CLI. You use the GUI pretty much all the time. Dump the windows and get a Linux install, try ubuntu and get used to using the well structured CLI. The GUI will make more sense then in general.
X Windows
gnome and kde
Yes
Linux is the kernel, from which many operating systems have branched out - Ubuntu and Linux Mint, to name but two. There is a Graphic User Interface (GUI) that allows a calculator to be used on the the desktop, or it is possible to calculate numbers using python terminal commands.