It depends on when it was made and if it's been upgraded. If it was brand new in 2012 then it could of came with 10.7.x or 10.8.x.
Apple is responsible for developing the Mac operating System.
Mac OS
Apple
One could run Windows XP on the Apple Mac if one were to essentially gut out the Apple Mac and turn it into a PC. There is no legal way of running a Windows operating system on top of an Apple operating system.
The Mac's operating system has evolved over several decades with contributions from numerous software engineers and designers at Apple.
Yes, a mac can if its running windows, but only the windows operating system will get it not the apple software itself>
Apple's Mac computers use their own operating system called Mac OS X. If required Windows can be installed and used on a Mac.
Mac OS X
Software is written to work with a particular operating system. Windows software requires the Windows operating system and Mac software requires Apple's Mac OS X. The two are not interchangeable. A Mac can run the Windows operating system and thus Windows software but Mac OS X can only be used on Apple's own computers.
As of Friday, September 23, 2011, Apple's latest operating system is Mac OS X Lion, or version 10.7.1.
Windows, Linux, Mac, apple operating system, sun OS
Mac OS