Overgrazing, overfarming, and the diversion of water for irrigation are significant causes of
a. deforestation
b. desertification
c. decreased agricultural production
d. shifting cultivation

Over grazing, over farming, and the diversion of water for irrigation are significant causes of desertification. From the name itself, it the process wherein a fertile land becomes a desert. It is a type of land degradation wherein a relatively dry land becomes increasingly barren losing its bodies of water, vegetation, and wildlife.

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.