What the difference between a cell and a molecule
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.
trees in bloom shed their leaves in winter to survive the harsh winters