instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Just as salty taste involves perception of sodium ions in saliva, sweet taste correlates with presence of glucose.
answer:
Just as salty taste involves perception of sodium ions in saliva, what taste correlates with presence of glucose?


question:
Multiple genes mutations is usually necessary to develop cancer.
answer:
What is usually necessary to develop cancer?


question:
Energy do ecosystems absorb on the earth.
answer:

What do ecosystems absorb on the earth?