For the answers, click on "Answers" at the bottom of this page (after question #22). x's being a square is a sufficient condition for x's being a rectangle. x's being a square is a necessary condition ...

But are these simple questions where cause-effect relationships can be predicted using necessary and sufficient conditions? Or, are they complex questions with interdependent variables and feedback?

These neurons manifest activation of AMP-activated protein kinase (AMPK), a metabolic sensor from yeast to mammals, during food deprivation, and this activation is necessary and sufficient for ...