Intrinsic Strange/Charmed Quarks Inside of a Strangeless/Charmless Hadron

We discuss few, apparently different, but actually tightly related problems: a)Strangeness in the nucleon; b) B --> eta' decays; c)Intrinsic charm in the proton spin problem. We argue that all these problems have a common origin and related to the OZI rule violation in 0^{\pm} vacuum channels . It leads to a noticeable role of a nonvalence component with 0^{\pm} quantum numbers in a hadron.}