Explain what a formal, functional, and perceptual region is and give an example each in your own words. I repeat, in your own words.

Functional regions are organized around a focal point; the metropolitan area of New York City is an example. Perceptual regions reflect people's feelings about certain areas; in the United States, southern California and the South each have a certain image.

the rub-al-khali is also known as the arabian desert and the "empty quarter"