In an Attempt to Stop Desertification, Some Groups Have Changed

In an attempt to stop desertification, some groups have changed the way they work with the land. They plant trees to stop erosion, build small barriers to slow water runoff on slopes, and bring food to their animals rather than letting them graze freely. Why would these techniques help stop desertification?

A) The trees increase evaporation.
B) They increase the amount of water used in the area.
C) People move out of the areas rather than follow these techniques, lessening the water demand.
D) They break up the cyanobacteria in the soil.
E) Trees, runoff diversion, and changes in grazing patterns all conserve water.