Operating System (OS)
The operating system allows the user to organize the computer's contents in a hierarchical structure of directories that include all of the following except:

System
Drives
Folders
Files

ANSWER DOWNLOAD EXAMIANS APP

Operating System (OS)
Semaphores

are used to do I/O
are used for memory management
synchronize critical resources to prevent contention
synchronize critical resources to prevent deadlock
None of these

ANSWER DOWNLOAD EXAMIANS APP