In the Middle East, early cultivation began as an attempt to copy, in a less favorable environment, the dense stands of wheat and barley that grew wild in the hilly flanks. All of the following either motivated or facilitated this attempt EXCEPT:.
A) population growth.
B) climatic changes that reduced the available amount of wild wheat and barley.
C) the existence of a vertical economy.
D) human inventiveness and experimentation that occurred in the optimal zones, such as the hilly flanks.
E) living in marginal areas most affected by climatic changes.