Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: The kidneys help the body maintain homeostasis in several ways. They filter all the blood in the body many times each day and produce urine. They control the amount of water and dissolved substances in the blood by excreting more or less of them in urine. Answer: the kidneys
Output:
Which body organ filters the blood in the body and creates urine?