Which of the following human activities result in arid patches of land?

(a) over cultivation

(b) restricted grazing

(c) felling trees

(d) poor irrigation practices

The development of the fertile top-soil takes centuries. But, it can be removed very easily due to human activities like over-cultivation, unrestricted grazing, deforestation (felling trees) and poor irrigation practices, resulting in arid patches of land. When large barren patches extend and meet over time, a desert is created.