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

[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?


[Q]: You see a faster reaction rate when the concentration of reactants is higher.
[A]: What kind of reaction do you see when the concentration of reactants is higher?


[Q]: Destructive interference in waves occurs two troughs what things overlap.
[A]:
Destructive interference in waves occurs when what things overlap?