Desertification extends beyond the expansion of existing deserts to include land degradation due to human activity in drylands. Land degradation destroys or reduces the productivity of the soil, and is caused by excessive and unsustainable activities such as deforestation, overgrazing, poor land management, soil salinization, and soil erosion.
Sure hope this helps you :D
What do you mean by responsible? Do you want to know the genetics behind it, what the surface markers do, or why they are metically important? I think I can help.
They are considered nonrenewable resources because once they are used, they are gone forever, and we are using way more than the Earth can produce. Your answer would be B!
Have a nice day! :)