Question: Several horses grazed in a fenced area across from a home. On rainy days, soil would wash down a slope and run toward the home. After the horses were moved a few years later, the soil no longer washed down when it rained. What could account for this change?

  Options: 
 A. The grass grew and kept the soil intact.
 B. The fence kept the soil contained.
 C. The soil was completely gone.
 D. The amount of rain decreased. 
Answer: A