Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Processing of filtrate in the proximal tubule helps maintain the ph level in body fluid.

Answer: Processing of filtrate in the proximal tubule helps maintain what level in body fluid?


Question: A decline in blood flow to kidneys organs stimulates release of the enzyme renin, in turn stimulating the reabsorption of sodium and water.

Answer: A decline in blood flow to what organs stimulates release of the enzyme renin, in turn stimulating the reabsorption of sodium and water?


Question: Ice wedging occurs because water expands.

Answer:
Why does ice wedging occur?