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: tree squirrels generate heat mainly by keeping their metabolic rate high.
What generate heat mainly by keeping their metabolic rate high?

Fact: creating wood-free paper does not require cutting down oaks.
What does not require cutting down oaks?

Fact: organisms that grow in pools on the cavern floor use poisonous darts for defense.

organisms that grow in pools on the cavern floor use what for defense?