Answer: D) All the above Explanation: An operating system has three main functions: (1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers, (2) establish a user interface, and (3) execute and provide services for applications software.

Answer: C) Backup file Explanation: In computing, ".bak" is a filename extension commonly used to signify a backup copy of a file.

Answer: D) Graphical User Interface Explanation: GUI stands for Graphical User Interface.   A Graphical User Interface is a computer interface that allows users to interact with a device through graphical elements such as pictures and animations, as opposed to text-based commands.

Answer: A) CPU Explanation: Central Processing Unit (CPU) is the brain of any computer system.

Answer: C) Delete a program from the hard drive Explanation: The task manager enables you to monitor processes, applications and services currently running on your computer. You can use it to start and stop programs and processes. In addition, you can use the task manager to show informative stats about your PC’s performance and network.   Hence, to delete a program from the hard drive, you have to go to the control panel to uninstall an application properly.

Answer: D) All of the above Explanation:

Answer: C) 8 bit Explanation: Word length refers to the number of bits processed by a computer's CPU in one go. These days, typically 32 bits or 64 bits are used. Data bus size, instruction size, address size are usually multiples of the word size.

Answer: B) Knowledge information processing system Explanation: