You are presented with the quiz "When a river floods, that river harms what?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "when a river floods , that river deposits soil in flood plains" and "soil erosion harms farm and grazing lands and increases flooding and desertification". 

So, what's the best answer to the question?


 

     farm and grazing lands      