Answer : 3. "Cow"
Explanation :

Loss of soil cover mainly due to rain or wind and surface runoff is the biggest cause of desertification. Climate change' and' human activities can be considered as the two main causes of desertification. Removal of natural vegetation cover – agricultural activities in vulnerable ecosystems of arid and semi-arid regions, by taking too much fuel wood, which are thus strained beyond their carrying capacity. The following factors cause desertification: Climate change – particularly long dry periods, leading to drought. Too many animals within the area – leading to overgrowth. Population growth – decline in traditional, less intensive, farming methods. Rajasthan is the state with the highest area of desertification in terms of total geographical area. The state has 62.90% of the total geographical area under desertification and land degradation for the period 2011–13. The UNCCD defines desertification as 'land degradation in dry, semi-arid and sub-humid areas, resulting in