Teacher:Given a scientific passage and an answer, generate a question for the given answer.
Teacher: Now, understand the problem? Solve this instance: Passage: Although the hillside is interesting, that's not why this was done. Terracing prevents soil erosion on a hillside that is being farmed. Many techniques can be utilized to reduce soil erosion. Answer: terracing
Student:
What prevents soil erosion on a hillside that is being farmed?