Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.

[Q]: Fact: roots have different meristems. 
Question: What do roots have?
[A]: meristems.


[Q]: Fact: the moon revolving around the Earth causes the new moon. 
Question: the moon revolving around the Earth causes what?
[A]: new moon.


[Q]: Fact: if ancient gastropod shells are found in a place then that place used to be covered by water. 
Question: the bones of what can be found to signify that place used to be covered by water?
[A]:
gastropod shells.