Read the passage carefully and attempt Questions  by choosing the most appropriate option: Desertification is a term used to explain a process of decline in the biological productivity of an ecosystem, leading to total loss of productivity. While this phenomenon is often linked to the arid, semi-arid and sub-humid ecosystems, even in the humid tropics, the impact could be most dramatic. The impoverishment of human-impacted terrestrial ecosystems may exhibit itself in a variety of ways; accelerated erosion as in the mountain regions of the country, salinization of land as in the semi-arid and arid ‘green revolution’ areas of the country, e.g., Haryana and Western Uttar Pradesh, and site quality decline – a common phenomenon due to general decline in tree cover and monotonous monoculture of rice/wheat across the Indian plains. A major consequence of deforestation is that it relates to adverse alterations in hydrology and related soil nutrient losses. The consequence of deforestation invariably arise out of site degradation through erosive losses. Tropical Asia, Africa and South America have the highest levels of erosion. The ultimate consequences of site desertification are soil degradation, alteration in available water and its quality and the consequent decline in food, fodder and fuel-wood yields essentials for the economic well beings of rural communities.