instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.
answer:
Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?


question:
All metabolic functions carried out by a prokaryote take place in the plasma membrane or cytosol else.
answer:
All metabolic functions carried out by a prokaryote take place in the plasma membrane or where else?


question:
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.
answer:
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?