Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: Just as salty taste involves perception of sodium ions in saliva, sweet taste correlates with presence of glucose.

A: Just as salty taste involves perception of sodium ions in saliva, what taste correlates with presence of glucose?
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Q: How much is involved in the reaction does the coefficient in front of an element in a formula indicate.

A: What does the coefficient in front of an element in a formula indicate?
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Q: High altitude above sea level causes the alpine tundra to be so cold.

A:
What causes the alpine tundra to be so cold?
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