1. Compact Disc Recordable (CDR) is a write-once-read-many (WORM) disc.

2. CD-R stands for Compact Disc Recordable and is a digital optical disc storage format.

3. A CD-R disc is a compact disc that can be written once and read multiple times freely.

The following devices are used to transmit network data.

- Microwave (Microweb)

- Infrared

- Radio Channel

1. The shortcut key to open File Explorer or File Manager is Ctrl + O.

2. In Microsoft Excel and all other spreadsheet programs, pressing Ctrl+O brings up the Open window, allowing you to load an existing spreadsheet stored on your computer.

3. In Microsoft Word and other word processors, pressing Ctrl+O brings up the Open window, allowing you to load an existing document stored on your computer.

1. A modem is used to connect the computer to the Internet through a phone line.

2. A modem converts digital information from your computer into analog signals that can be transmitted over wires (and vice versa).

1. An operating system is not HP.

2. The full name of HP is Hewlett-Packard. It is an American multinational information technology company that manufactures and sells computer hardware, software, and services.

In a hierarchical database model, a parent record type can be associated with one or more child record types, but a child record type can have only one parent. This hierarchical structure is represented as a tree-like schema, where each parent record can have multiple child records, but each child record has only one parent. This model is useful for representing data with hierarchical relationships, such as organizational structures or file systems.