Computer Science

The welcome screen in most operating systems displays the names of all user accounts on the computer, allowing users to select their profile to log in. This matches option B, making it the correct answer.

RAM stands for Random Access Memory, which is a type of computer memory that can be accessed randomly at any time, regardless of physical location in memory.

The '@' symbol is used to separate the local part and the domain part of an email address, effectively dividing the email into two parts.

The font size tool in many MS Office applications can be accessed quickly using the shortcut Ctrl + Shift + P, which opens the font size dialog box. The other options do not correspond to font size adjustment shortcuts.

CSS stands for Cascading Style Sheets, which is the correct and widely accepted full form used in web development for styling web pages.

The Internet is commonly referred to as both "a network of networks" because it connects multiple smaller networks, and "the Net" as a popular shorthand. Therefore, option C, "Both," is correct.

Twitter was launched in 2006, making option A the correct answer. The other years listed are incorrect for Twitter's launch date.

Input devices like keyboards and mice are used to enter or input information into a computer system, making option B the correct answer.

Ctrl + Y is the standard keyboard shortcut for the 'Redo' action, which reverses the last 'Undo' command in most software applications.

HTML stands for Hypertext Markup Language, which is the standard language used to create and design web pages. Option B correctly reflects this full form.

CRT stands for Cathode Ray Tube, which is a technology used in older types of computer monitors and televisions. Therefore, CRT is a form of monitor.

HTML (HyperText Markup Language) is used to create and structure webpages, which are the individual documents displayed in web browsers. Websites are collections of webpages, so HTML directly creates webpages.

CPU stands for Central Processing Unit, which is the primary component of a computer that performs most of the processing inside a computer.

Cache memory is a small, fast memory located inside or very close to the CPU to speed up access to frequently used data and instructions, improving overall processing speed.

CU stands for Control Unit, which is a key component of a computer's CPU responsible for directing operations within the processor.

CSS stands for Cascading Style Sheets, which is the correct and widely accepted full form used in web development for styling web pages.

LED stands for Light Emitting Diode, which is a semiconductor device that emits light when an electric current passes through it. This is the widely accepted and correct expansion of the acronym LED.

PB is the abbreviation for Petabyte, a unit of digital information storage. 'Plumber' is unrelated to this abbreviation in computer science context, so option A is correct.

The '@' symbol is used in email addresses to separate the local part (username) from the domain part, effectively dividing the email into two parts.

The font size tool in many word processing software can be accessed quickly using the shortcut Ctrl + Shift + P, which opens the font size dialog box. The other options do not correspond to font size adjustment shortcuts.

CSS stands for Cascading Style Sheets, which is the correct full form used in web development to describe the style and layout of web pages.

CSS stands for Cascading Style Sheets, which is the correct full form used in web development to describe a style sheet language used for describing the presentation of a document written in HTML or XML.

The '@' symbol is used in email addresses to separate the local part (username) from the domain part, effectively dividing the email into two parts.

CSS stands for Cascading Style Sheets, which is the correct and widely accepted full form used in web development to describe the style sheet language.

The '@' symbol is used to divide an email address into two parts: the local part (username) and the domain part (mail server). This is the standard format for email addresses.