In this paper the next attempt is made to clarify the nature of the Euclidean behavior of the boundary in the angular size-redshift cosmological test .
It is shown experimentally that this can be explained by the selection determined by anisotropic morphology and anisotropic radiation of extended radio sources .
A catalogue of extended radio sources with minimal flux densities of about 0.01 Jy at 1.4 GHz was compiled for conducting the test .
Without the assumption of their size evolution , the agreement between the experiment and calculation was obtained both in the \Lambda CDM model ( \Omega _ { m } = 0.27 , \Omega _ { v } = 0.73 . )
and the Friedman model ( \Omega = 0.1 ) . DOI : 10.1134/S1990341314040026