Biological sciences NATURALIST REGIONAL STUDIES OF SAMARA REGION 5-20 VDR GENE EXPRESSION AND LEUKEMIA DEVELOPMENT 21-25 ABOUT HETEROSIS AND DOMINATION AT HYBRIDS F1 OF POTATO 26-29 ECOLOGICAL ETHICS AS A PHILOSOPHICAL PHENOMENON 30-51 MAMMALS (MAMMALIA) AVERAGE VOLGA REGION PLEISTOCENE TO MODERN 52-77