degradation of nutrients due to pesticides formation of deserts due to tree felling flooding due to dam construction removal of nutrients due to heavy rains
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Soils change both through natural processes and as a result of human activity. Which of the following soil changes is due only to natural causes?
Possibilities:
- degradation of nutrients due to pesticides
- formation of deserts due to tree felling
- flooding due to dam construction
- removal of nutrients due to heavy rains

removal of nutrients due to heavy rains