Answer: human activity
Explanation:
Desertification is a kind of land degradation in which a dry land is converted into desert. Desertifcation occurs when the area receives very low annual rainfall. The desertification can be caused by variety of factors like change in the climatic conditions and human activities. It involves hot and dry climatic conditions, the available water bodies get dry up and vegetation cover get reduced. The desertification occurs due to human activities due to over-exploitation of the land. The land is over-exploited by over farming, mining and deforestation. Due to these effects the land looses it's fertility, the climatic condition changes and the region receives very low annual rainfall, the water cycle of the region is affected and the water reserve get dry out.
