Answer:
Ram and the hard drive
Explanation:
A page of RAM is written to the harddisk and read back when it is needed again. That way it may seem you have more RAM than you actually have, at the cost of performance of course.
The answer is true. The Undo command is set up on the toolbar. You can undo up to 40 edits in your plan by clicking on the Undo button. If you want to undo all of the revises made, simply quit (close your Internet browser window or start a new plan) without saving.