Answer:
Hunter gatheres gathered food only and farming societies only farmed for food
The most often used application of the term virtuosity applies to music - a virtuosic piece, a virtuosic musician etc. Thus the answer to this is b. Virtuosity means extreme technical proficiency in an area of music (though it can be applied to other things as well to show mastery of a skill - a virtuosic painter etc.)
I'm guessing you mean in Photoshop so you would
1. click the ruler tool
2. drag it along the line you know is straight
3. on the options bar, click straighten
hope this helps :)
Self-publishing is the publication of media by its author without the involvement of an established publisher. The term usually refers to written media, such as books and magazines