2385. What character can be added to both of these characters to give other characters? 止_ -> _包

止  SHI, to(meru), to(maru) - stop

包  HOU, tsutsu(mu) - wrap

Add 月:止+月 月+包   

月  GETSU, GATSU, tsuki - moon, month

肯  KOU - agree, consent

胞  HOU - sac, sheath, placenta