How can the rise of the ancient Russian principality be explained to a greater extent: by natural or human factors?

Rather, the human factor. Ancient Russia developed precisely thanks to the clever policies of its princes. So Prince Oleg became the one who for the first time united the Slavic tribes and expanded the borders of Russia itself. Princess Olga pursued active diplomacy and effective domestic policy. Thanks to his military campaigns, Prince Svyatoslav was able to defeat the evil enemy of Russia – the Khazar Kaganate, and also significantly expand the territory of the State. The list of the princes’ deeds can be continued for a long time.