TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: The long bone work as lever.

SOLUTION: What type of function does the long bone perform?

PROBLEM: A diet rich in calcium and vitamin d may reduce the risk of osteoporosis and related bone fractures.

SOLUTION: A diet rich in calcium and what vitamin may reduce the risk of osteoporosis and related bone fractures?

PROBLEM: Nitrogen oxide form(s) when nitrogen and oxygen combine at high temperatures.

SOLUTION:
What forms when nitrogen and oxygen combine at high temperatures?