To Rely/count on Someone, to __ on Them
Puzzle 19 of Quiet Things Piece of Cake Pack
Question is: To Rely/count on Someone, to __ on Them
and the answer is: DEPEND
Word Meaning:
DEPEND — (intransitive) To be contingent or conditioned; to have something as a necessary condition [with on or upon; or (obsolete) with of]
Definitions from Wiktionary.