What characterizes a web server?

A web server is defined by its primary function of responding to requests for web content. When a user enters a URL in their web browser or clicks on a link, the browser sends a request to the web server that hosts the website's content. The web server processes this request and sends back the appropriate web pages, which may include HTML files, images, and other resources. This interaction facilitates the delivery of content over the internet, making web servers essential for the functioning of websites.

In contrast to this, the other choices describe functionalities that do not align with the role of a web server. A computer designed solely for personal use implies a focus on individual computing rather than serving content over the internet. Similarly, a computer running only antivirus software would not serve web content; this type of software is meant for security rather than web serving. Lastly, a device distributing power to network devices does not involve web hosting or content delivery, highlighting distinctions in functionality.