Unix Operating system questions

1. Linux partitions are created using the file system is EXT3.
2. /etc sub directory contains system configuration files include user passwords.
3. PATH is the environment variable in Linux, that contain a list of directories the shell automatically recognizes.
4. FORK is a system call in Linux operating system to create a new child process, which is a copy of the parent process.
5. put is not an Unix Command ? 
6. The usage of "nice" command is:  To increase or decrease the priority of a process
7. Most found unix directory is "usr"
8. Memory management system call is "mmap"
9. What OS treates a hardware as a file system "UNIX".
10. unix prompt for changes permission to deny write permission to group and others?Chmod go-w filex.