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Starburst events in dwarf galaxies, with stellar mass ~10^9 – 10^10 Msolar and with typical metallicity [O/H] > -1.0, are known to be responsible for the formations of young/intermediate-age massive star clusters (YIMSCs), with typical masses falling in the range of the globular cluster (GC) mass. These events and the formation of the YIMSCs are widely believed to be an accidental process fully dependent on and driven by external factors, such as merging or strong interactions. However, nearly ten years ago, analyzing a variety of data available and published to date, we argued, for the first time, that the formation of both the YIMSC populations in dwarf (irregular) galaxies and the populations of metal-rich GCs in spheroids occurs at approximately the same stage of the host galaxies' chemical evolution. It is related to the essentially increased star formation (SF) activity in the hosts around the same metallicity , ~1/3 of the solar one. It is achieved very early in massive spheroids, later in lower mass spheroids, and much later in irregular galaxies. In the present contribution we demonstrate one more piece of supporting evidence of essentially increased SF activity in dwarf galaxies around this particular metallicity. This observing evidence is based on published direct estimates of both relative SF rate and metallicity (oxygen abundance) in a very large sample of star-forming galaxies in the nearby Universe, at very low redshift.