Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Wind blows small particles away. As a result, the ground surface gets lower and rockier; this is called deflation . The rocks that are left are called desert pavement . Desert pavement is a surface covered by gravel-sized particles that are not easily moved by wind. Answer: deflation
Output:
What is the process by which wind blows to make the ground surface gets lower and rockier ?