Still not following. Believe me, I&#x27;m really trying, but something seems off. Maybe an analogy would help.<p>We have two populations A and B. A has walked slower than B. One individual, a1, says &#x27;hey I suspect B (who controls the food) is withholding vitamin X&#x27;. Evidence is uncovered showing this to be true. A is given vitamin X, and A begins to walk faster.<p>However a subset of A still doesn&#x27;t walk as fast. Again, an investigation is done, and it&#x27;s shown that B has also been withholding vitamin Y. After vitamin Y is given, that subset of A also begins to walk faster.<p>Then, a smaller subset of that subset shows initial gains in walking speed, but recently their speed has dropped off significantly. So, A is given even more vitamin X and Y. But, that doesn&#x27;t help. So, instead of suspecting that B is withholding vitamin Z, we should take them on their word that recently the terrain has changed so that B just naturally walks faster than A?