TASK DEFINITION: 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?"
PROBLEM: Fact: reproduction requires pollen.

SOLUTION: what is required for reproduction?

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

SOLUTION: What does not require cutting down oaks?

PROBLEM: Fact: Vapor pressure  is when liquids are heated.

SOLUTION:
Vapor pressure is caused when?