instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
The human eye detect can detect three colors of light.
answer:
How many colors of light can the human eye detect?

question:
Mucous does the esophagus produce for lubrication.
answer:
What does the esophagus produce for lubrication?

question:
Nitrogen has 5 valence electrons.
answer:
How many valence electrons does nitrogen have?