Turn the given fact into a question by a simple rearrangement of words. This typically involves replacing some part of the given fact with a WH word. For example, replacing the subject of the provided fact with the word "what" can form a valid question. Don't be creative! You just need to rearrange the words to turn the fact into a question - easy! Don't just randomly remove a word from the given fact to form a question. Remember that your question must evaluate scientific understanding. Pick a word or a phrase in the given fact to be the correct answer, then make the rest of the question. You can also form a question without any WH words. For example, "A radio converts electricity into?"

Fact: passive immunity lasts only as long as the gammaglobulins survive in body fluids.
passive immunity lasts only as long as what survives in body fluids?

Fact: Thirst is used to make a cow realize that it needs to replenish its bodily water by the body.
Thirst is used to make a cow realize that it needs to replenish its bodily what by the body?

Fact: carbon may be stored in limestone for millions of years.

What may be stored in limestone for millions of years?