Surface run off is a kind of water erosion in which the surface layers of the top soil containing minerals and sediments is wiped out by the water and deposited to some other place. In the given situation, the surface run off of the farmer's field close to the stream will likely to remove the fertilizers hence,the level of the fertilizers in the stream is likely to increase.
Student 1’s methods would be more accurate, because the student would control more factors. Only one variable at a time (either temperature or acidity) would be tested on each group of worms. On the other hand, Student 2 is testing both factors on all the worms, which could make the results unclear.
