instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
The pressure of a sample of gas is measured with an open-end manometer.
answer:
The pressure of a sample of gas is measured with an open-end what?


question:
Over 90% of the energy we use comes originally from the sun.
answer:
Over 90% of the energy we use comes originally from what?


question:
When blood vessels in the head dilate, a migraine, a severe headache, can occur.
answer:

When blood vessels in the head dilate, what kind of severe headache can occur?