instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
The long bone work as lever.
answer:
What type of function does the long bone perform?

question:
It takes about one year for earth to orbit the sun.
answer:
Which of these takes about one year to complete?

question:
Primary pollutants enter the air directly.
answer:
What type of pollutants enter the air directly?