Because it allows their files to be accessed from any device on the Internet, many users like to back-up their files using ___ storage.

Cloud

Explanation:

Cloud computing is a central form of storing data on a data center, provided online, to provides inexpensive and secure storage facilities and central accessing of document, using any device and accessing the data from anywhere and time.

Data stored in a clients computer system, would have to be transferred to another remote computer by using a portable storage, to share data. Using a cloud service or a database center service, a document can be accessed by a group of users at the same time, in different places, and assures a secure data in the database.