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: Vertebrates have a complete digestive system and a closed circulatory system.
What do all vertebrates have?

Fact: liquid propane is used to expand hot air balloons.
How is liquid propane used in hot air ballooning?

Fact: magnifying objects hundreds of thousands of times is used for seeing very small objects by making them appear bigger.

magnifying objects hundreds of thousands of times is used for seeing what?