Which device is NOT typically part of a network's backbone?

In the context of networking, the backbone refers to the principal data routes of a network that connect different segments and carry the majority of the data traffic. To understand why a computer monitor is not typically part of a network's backbone, it’s essential to recognize the roles of the other devices.

Routers and switches are critical components of a network backbone. Routers direct data packets between different networks, while switches connect devices within the same network, managing data traffic efficiently. Communication links, which include various media such as fiber optics or cables, facilitate the physical transfer of data across the network backbone.

A computer monitor, on the other hand, is an output device that displays information to users. It does not play a role in directing, switching, or transferring data within the network structure. Therefore, it does not contribute to the functioning of the network backbone, making it the correct choice as the device that is not typically part of this foundational element of networking.