Where does “просити” come from?

просити (Old East Slavic) comes from Proto-Slavic prositi, from Proto-Balto-Slavic práśīˀtei, from Proto-Indo-European preḱ-, from Proto-Indo-European pr̥ḱneh₂.

Ancestry of “просити”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	prositi	to ask
2	Proto-Balto-Slavic	práśīˀtei	to ask
3	Proto-Indo-European	preḱ-	to ask
4	Proto-Indo-European	pr̥ḱneh₂	—

Every word from Proto-Indo-European pr̥ḱneh₂ →Every word from Proto-Indo-European preḱ- →Every word from Proto-Balto-Slavic práśīˀtei →