TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: One gram of sugar or starch provides 4 calories of energy.

SOLUTION: How many calories of energy does one gram of sugar or starch provide?

PROBLEM: On a global scale, plants and other photosynthetic organisms have generated all of the oxygen in the air.

SOLUTION: On a global scale, plants and other photosynthetic organisms have generated all of what element in the air?

PROBLEM: Cations are formed by the loss of one or two electrons from an element.

SOLUTION:
What are formed by the loss of one or two electrons from an element?