Evaporation for the first one
Dry climates have unreliable year-to year precipitation and have a moisture deficit - potential evapotranspiration exceeds precipitation. These climates dominate large portions of the subtropics and extend into the interiors of continents in the middle latitudes and cover nearly one-third of Earth’s lands surface. Desert (BW)
A. by suppressing political opposition to the country’s policy of economical diversification