yes there is mac and there is Linux
The Linux kernel. Beyond that, there are numerous alternative implementations of virtually every Linux program.
Absolutely - Linux is an alternative (though less-popular) operating system to Windows.
Octavia butler received her education at biblical high an alternative middle/ high school.
There is no "the startup file" in Linux; depending on the type of system, there may not be any files at all. The Linux boot process has a number of steps, many of which are optional or have alternative implementations.
Yes. Valve has released the Linux version of Steam, and there is a steadily-increasing number of games in Steam that are playable in Linux (and some of them are cross-platform, like Portal, Team Fortress, Left 4 Dead, etc). As an alternative, Valve also released SteamOS (which is based on Linux).
Linux is a free Open Source Operating System, based on Unix. It is available from many vendors with optional paid for support and provides an increasingly viable alternative to the Win 32 platform.
Ubuntu is a complete Linux-based operating system, freely available, with both community and professional support. And there are several alternatives, including OpenSUSE, PCLinuxOS, Freespire and Linux Mint.
The Linux operating system was created by Linus Torvalds, who announced its development in August 1991. The first official version, Linux 0.01, was released in September 1991. While Linux is often associated with servers today, its initial purpose was to be a free alternative to the MINIX operating system for personal computers. Over the years, it evolved into a robust platform widely used for server environments.
Yes if you install the correct hardware and software. (I'd suggest sending a .pdf by mail instead if that is a viable alternative)
Generally speaking, Alt+F1. However some DEs do accept Windows/Super key as an alternative.
LDAP (Lightweight Directory Access Protocol) often used in Unix and Linux environments, Active Directory is based on LDAP.