  The visible Universe is largely characterised by a single mass-scale; namely,
the proton mass, $m_p$. Contemporary theory suggests that $m_p$ emerges as a
consequence of gluon self-interactions, which are a defining characteristic of
quantum chromodynamics (QCD), the theory of strong interactions in the Standard
Model. However, the proton is not elementary. Its mass appears as a corollary
of other, more basic emergent phenomena latent in the QCD Lagrangian, e.g.
generation of nuclear-size gluon and quark mass-scales, and a unique effective
charge that may describe QCD interactions at all accessible momentum scales.
These remarks are explained herein; and focusing on the distribution amplitudes
and functions of $\pi$ and $K$ mesons, promising paths for their empirical
verification are elucidated. Connected therewith, in anticipation that
production of $J/\psi$-mesons using $\pi$ and $K$ beams can provide access to
the gluon distributions in these pseudo-Nambu-Goldstone modes, predictions for
all $\pi$ and $K$ distribution functions are provided at the scale
$\zeta=m_{J/\psi}$.
