A secondary source is directly related to the event or historical figure you are researching, such as a photograph from the event. 

Corona and App Inventor can be used to develop ________

A) Web pages B) Mac software C) apps for smartphones D) complex web applications

Most operating systems create a significant number of temporary files in the course of operation. Which one of the following might leave behind "footprints" if the computer is not shut down gracefully?

a. Autosave files b. Print spooler files c. Undo files d. All of the above