Do you mean ion pumps in the membrane of cell?
If so, then ion pumps maintain an electrochemical gradient across the membrane.
In this question, austin turk and many other conflict criminologists see crime as a natural consequence of inter group struggles over control. although crime is commonly define as an unlawful act of someone and is punishable by the state or other authority. And it is also define as not just an act but as an illegal act.
Answer:
When it stands the test of time and is supported by many experiments.