1389. What character can be added to both of these characters to give other characters? 苗_ -> _反

Answer:

苗  BYOU, nae, nawa - seedling, sapling

反  HAN, HON, tane, so(ru) - anti-, bend back

Add 木:苗+木 木+反 

木  MOKU, BOKU, ki - tree

菓  KA - cake, fruit

板  HAN, BAN, ita - board