What have sociologists begun to realize about the nomadic lifestyle?
a. nomads have a hard time bridging the gap between their traditional lifestyle and doing what is best for the land.
b. nomads never tire the land they live on because they are constantly moving from place to place.
c. nomads are better than stationary farmers at protecting the land and keeping the soil good for other people's use.
d. nomads only raise sheep and goats, not cows or oxen, so the grass their herds consume is minimal at most?