質問: what is the difference between 返答 and 返事 and 回答 and 答え ? what is the difference between 返答 and 返事 and 回答 and 答え ?
回答: and 返事works 99% cases. you can use 返事instead 回答and 返答. but in some cases if you use 回答 or 返答instead 返事, it will probably be unnatural like this. 彼からパーティーへの招待の回答/返答が来ない is a little bit unnatural. 返事is casual yet polite.