报答 reflects the deep Confucian value of reciprocity (报恩 bào'ēn). Repaying parents, teachers, and benefactors is considered a fundamental moral duty in Chinese culture.
usage
报答 (repay kindness) vs 报仇 (bàochóu, take revenge) vs 报恩 (bào'ēn, repay a debt of gratitude) — all use 报 in the sense of 'returning' something.