Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Superior sagittal sinus is the largest of the sinuses.

Answer: What is the largest of the sinuses?


Question: When an atom gains or loses an electron it becames a(n) ion.

Answer: When an atom gains or loses an electron it becames an?


Question: Bond energies can be used to estimate the energy change of a chemical reaction.

Answer:
What can be used to estimate the energy change of a chemical reaction?