2163. What characters can be added here so that each character contains a part of the previous character? a) 炎 -> _ -> _ -> 胞 b) 妙 -> _ -> _ -> 嘱

a) 炎 -> 炉 -> 肩 -> 胞  

炎  EN, honou - flame

炉  RO - furnace, hearth

肩  KEN, kata - shoulder

胞  HOU - sac, sheath, placenta

b) 妙 -> 劣 -> 加 -> 嘱  

妙  MYOU - strange, odd, adroit, mystery

劣  RETSU, oto(ru) - be inferior

加  KA, kuwa(eru), kuwa(waru) - add, append, join, take part

嘱  SHOKU - request, entrust, commission