'Climatic variations' and 'Human activities' can be regarded as the two main causes of desertification. removal of the natural vegetation cover（by taking too much fuel wood）, agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.
I think 1991 it was the fall of soviet union
~Hello there! ^_^
Your question: What waterway is the most significant to the regions due to its vast resources..?
Your answer: Tigris River is the water way that is the most significant to the regions to its vast resources.
The answer is option C.
Hope this helps~
Kim Kardashian is Persian.
