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

SOLUTION: 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?

PROBLEM: In science, theory is supported by much evidence, widely accepted by credible scientists, and unlikely to be disproved.

SOLUTION: In science, what is supported by much evidence, widely accepted by credible scientists, and unlikely to be disproved?

PROBLEM: All mammals have four limbs.

SOLUTION:
How many limbs do all mammals have?