The answer is D) desertification and deforestation
To know the answer you can rule out the non-possibilities. A is not correct because farmers use them all the time. B is not correct because water and pesticides can flow downstream and carry and deposit sediment. C is not correct because farmers can flood their own farms. When they plant things and a food comes, all of those plants will die or their roots will detach which lowers the food that can be sold. D is correct because farmers don't farm in the desert or the forest, so it would not be an impact of farming.
 
        
             
        
        
        
Answer:  "mutations" .
_______________________________________
        
             
        
        
        
This can happen because you have recessive and dominant characteristics passed down. So you can get a totally different chromosome that doesn't come from your parents because your grandparents may have had it or great grand parents, the line keeps going .
        
             
        
        
        
Answer:
Positive feedback is most like adding wood to a burning fire to increase the heat. Positive feedback is a regenerative feedback process in which a segment of the output is combined with the input for the output to increase more.
Explanation:
Hope this helps :)