  We discuss the link between the chiral symmetry of QCD and the numerical
results of the light-front quark model (LFQM), analyzing both the two-point and
three-point functions of a pseudoscalar meson from the perspective of the
vacuum fluctuation consistent with the chiral symmetry of QCD. The two-point
and three-point functions are exemplified in this work by the twist-2 and
twist-3 distribution amplitudes of a pseudoscalar meson and the pion elastic
form factor, respectively. The present analysis of the pseudoscalar meson
commensurates with the previous analysis of the vector meson two-point function
and fortifies our observation that the light-front quark model with effective
degrees of freedom represented by the constituent quark and antiquark may
provide the view of effective zero-mode cloud around the quark and antiquark
inside the meson. Consequently, the constituents dressed by the zero-mode cloud
may be expected to satisfy the chiral symmetry of QCD. Our results appear
consistent with this expectation and effectively indicate that the constituent
quark and antiquark in the LFQM may be considered as the dressed constituents
including the zero-mode quantum fluctuations from the vacuum.
