[ros-general] New to ReactOS

[Redefined Horizons]

I have just migrated from Windows to Linux, and I am very curious about
ReactOS. I have a couple of newbie questions I was hoping I could get
answered. (I have already checked the developer and user FAQs on the ReactOS
website.)
 [1] Is ReactOS built on a Unix core, or is it a new operating sytem from
the ground up?
 [2] Can you dual boot with ReactOS and a Linux operating system like
Debian? If you can, is there a place where I can find instructions on how to
do so?
 [3] Does an application that runs on Microsoft Windows have to be ported
before it can be run on ReactOS? Can I try installing the program to see how
it works?
 Thanks,
 Scott Huey