Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Fresh water is essential for good crops. In some areas of the world, there is enough rain to accomplish this task. In other locales, water must be provided so the crops will grow. Worldwide, irrigation covers about 18% of farm land and produces some 40% of crops. A major source of cleaner water in many parts of the world is provided by the process of desalinization . Answer: process of desalinization
Output:
Which process helps provide cleaner water for agriculture?