Desertification and deforestation are a. environmental challenges facing the sahel c. economic issues facing the sahel b. issues the sahel nations have solved in recent years d. the reasons the sahel cannot get foreign aid

i believe it is capitalists.  

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."