Final answer:
The mobile device is primarily operated by a touchscreen, especially in contrast to notebooks, desktops, and networks which may have the capability but do not use it as the main form of interaction.
Step-by-step explanation:
The device that is primarily operated by a touchscreen is the mobile device. Over time, personal computing has shifted greatly towards convenience and portability, with the mobile device at the forefront of this evolution.
Unlike the Notebook, Desktop, and Network, which may utilize touchscreens but do not rely on them as their primary method of interaction, mobile devices such as smartphones and tablets are designed with touchscreens as the main interface for user input and navigation.