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?"

[EX Q]: Fact: Plasma cells are activated B cells that secrete gammaglobulins.
[EX A]: What is secreted by plasma cells (activated B cells) ?

[EX Q]: Fact: Wheat supplies food consumed by people.
[EX A]: What supplies food consumed by people?

[EX Q]: Fact: Many cancers can cause the immune system to not work properly.
[EX A]:
Many _ can cause the immune system to not work properly.?