________ is the degradation of land in arid, semi-arid and dry sub-humid areas.

Ecosystem is a biological community of interacting organisms and their physical environment. Ecosystems can be classified into different types, based on their climate, vegetation, and other characteristics. Ecosystems are important because they provide a number of services to humans, including food, water, and clean air.

Vegetation is the plant life of a particular area. It is affected by a number of factors, including the climate, the soil, and the human activities. Vegetation can be improved through a number of methods, including planting trees, shrubs, and grasses.