Fact 1: Drought is when amount of precipitation decreases.

Fact 2: Drought causes famine, which contributes to decentralization and unrest.

Given the two facts above, answer the question "What can cause famine?" with the following options: 
- Movement of an air mass
 - Effective fertilizers
 - the ground shaking
 - Increased irrigation
 - Crop harvesting
 - Decreased precipitation
 - single-celled organisms
 - forest is destroyed


 

      Decreased precipitation   