And sometimes, it depends...

For #1 (where is are the latest database changes recorded and what would you do to preserve that particular piece of disk?)

For #2, it depends. The answer you gave will verify that your backup matches your database, but if your database is corrupted, you might just be backing up corruption. See Grant Fritchey's excellent backup article on this site. Hint (your backups are only as good as your restores).

For #3 I've run out of clever hints and must fall back on the general consensus that Google is your friend (or even a search on SSC).

And generally, it's a better idea to learn how to search for these answers yourself than have people give them to you. I'm willing to bet that you'll hit one of these interesting dilemas some night when most of the Illuminatti are asleep (well maybe not Gail), and you'll be in a complete mess without the ability to hide from the red glowing eyes of your Boss (who thought he was hiring an experienced DBA).

Look up the answers, post what you think they are, and maybe someone will jump in and correct you if you're off base.