Select each correct

Which of the following land use choices could lead to desertification?
1. removing all of the plants from a region
2. farming a region's soil heavily for many years
3. allowing livestock to overgraze a region

Allowing livestock to overgraze a region leads to desertification of land

Explanation:

Desertification is the conversion of a once fertile vegetative land to a barren land due to environmental changes. Many human activities and practices are often the cause of desertification of fertile lands.

Overgrazing plays a major role in desertification of lands. When huge number of farm animals is made to graze over vast lands, the entire vegetative cover will be lost.

When there is less protective vegetative cover, then the land becomes dry and barren allowing very less infiltration of ground water which reduces moisture content of the soil. This finally results in land becoming dry and deserted and the precipitation also becomes less. All these conditions recycle and reduce the vegetative growth.  

Unsustainable agricultural practices like growing heavily or intensive farming or removing plants in a region also causes desertification, but land use by overgrazing contributes more to desertification.

genetic variation will increase because of a new habitat and food source.

explanation:

a metamorphic rock would be formed.