What is the World Wide Web?

The World Wide Web refers to a vast information system that is accessed via the internet and primarily utilizes the Hypertext Transfer Protocol (HTTP) to transmit data. It encompasses web pages and websites, which contain text, images, videos, and links that allow users to navigate between different resources. This system relies on the internet's infrastructure to function but is specifically focused on web content that can be accessed through web browsers.

The other options do not accurately represent the nature of the World Wide Web. A computer virus is malicious software designed to harm or interfere with computer systems, which is unrelated to the web. A web-based email client is a specific application used to access email over the web, but it does not encompass the broader concept of the World Wide Web itself. Similarly, applications for chat services are specific functionalities that may operate on the web but do not define it. Therefore, understanding that the World Wide Web is a subset of the internet that uses HTTP is essential for grasping its role in facilitating access to information and services online.