Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: Saturated hydrocarbons hydrocarbons contain only single bonds between carbon atoms.

A: What hydrocarbons contain only single bonds between carbon atoms?
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Q: The human eye detect can detect three colors of light.

A: How many colors of light can the human eye detect?
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Q: The ileocecal valve, a sphincter, is usually in a constricted state, but when motility in the ileum increases, this sphincter relaxes, allowing food residue to enter the first portion of large intestine.

A:
The ileocecal valve, a sphincter, is usually in a constricted state, but when motility in the ileum increases, this sphincter relaxes, allowing food residue to enter the first portion of what?
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