If an area has low density but people are concentrated in small valleys rather than hill slopes, what is confirmed?

Correct answer: Local residential selection exists within the average density

Correct answer: A. Average density is calculated for the whole area, so it can hide important local differences. A region may have low overall density because large hill slopes or other difficult locations contain few people, while small valleys contain many of the residents. Valleys may offer gentler land, water, routes for travel, farmland or easier sites for houses, although the exact reason can vary from place to place. B is incorrect because concentration in valleys proves that settlement is not uniform. C is incorrect because the stated concentration shows that valleys matter to local settlement. D is incorrect because language alone cannot explain the physical pattern described. The important distinction is between average density and the distribution of people inside the area. Memory cue: an average is a summary; it does not mean every part is equally populated.