Here, within the Scale-Symmetric Theory (SST), we described the dark-matter mechanism which leads to the equality of orbital speeds of stars outside the central stellar bulge of spiral galaxy. The obtained results are consistent with the observational facts for the Milky Way, Andromeda Galaxy, Triangular Galaxy and SBO-a NGC 4984. The equality of orbital speeds of stars for defined spiral galaxy follows from the weak interactions, via leptons, of the baryonic matter with the virtual dark-matter loops in the Einstein spacetime - the loops mimic the motions in fermions. The ordered motions of matter along the jets of quasars produce flows in the Einstein spacetime. Such motions decrease local dynamic pressure in the spacetime i.e. there are produced pressure holes. To increase the lowered dynamic pressure, there are inflows of additional Einstein-spacetime components into the pressure holes but mass density is still to low to produce real particles. Such regions with higher local mass density of the Einstein spacetime mimic gravitational attraction so there appears the gravitational lensing. During the initial period of evolution of quasars, the iron-plus-nickel lumps from the explosions of the Population III supernovae (the first-generation big stars) mainly collected in the regions with higher local mass density of the Einstein spacetime so there appeared the ferromagnetic filaments between the quasars. We do not need some exotic matter to explain the origin of dark matter and dark energy - they both are the additional entangled or free neutrino-antineutrino pairs (the free pairs interact gravitationally only). We calculated as well the “mass ratio” of the dark matter and visible matter for galaxies, dwarf-galaxies and ultra-faint galaxies (dSphs). For the dwarf galaxies with active dark-matter mechanism, the ratio is up to 1000 and more.