Kaknaeva Margarita S. RussiaNizhny NovgorodLobachevsky State University of Nizhni Novgorod, 23 Gagarin Avenue, Nizhni Novgorod 603950, Russiakanaeva543221@gmail.com Author's articles Functional activity of the immune system of Pelophylax ridibundus (Amphibia: Ranidae) in environmental stress conditions