Answer:
Khan Academy is the best app for education, you can watch videos and do quizes
A consistent database base is one in which all data integrity constraints are satisfied.
U can use Bluetooth connect your computer to the android. <span />
Answer:
PDF (Portable Document Format)
Explanation:
The PDF file extension indicates that a file is an Adobe Acrobat document. Adobe developed a file format called Portable Document Format (PDF) in the 1990s to display documents that can include images, text, links, buttons, audio, video, form fields etc in such a way that it is not dependent on a specific Operating system, software or hardware.
The PDF file extension is cross-platform which means that the PDF file can be viewed on any Operating System such as Windows, Linux, macOS, Android, IOS etc.
The statement that best describes the role of folders in your operating system is that Foldoers allow you to organize and maintain files (letter B).
Folders are useful for separating file types and folders are also useful for organizing programs or files on your personal computer.