A tree or hierarchical directory structure begins with the _____ directory. 1. Top level 2. Node 3. Root 4. Leaf In the UNIX system, a file link allows _______. 1. File sharing 2. File counting 3. File deletion 4. Reference counting The set of UNIX file permissions -rwxr-xr ensures that "all others" will have ______ access to the file. 1. Read, write, and execute 2. No 3. Read and execute 4. Read The superblock of a UNIX file system contains____. 1. Size information 2. inodes 3. Free block information 4. All the above