2407. What characters can be added here so that each character contains a part of the previous character? a) 粒 -> _ -> _ -> 肺 b) 早 -> _ -> _ -> 販

a) 粒 -> 音 -> 明 -> 肺  

粒  RYUU, tsubu - a grain

音  ON, IN, oto, ne - sound

明  MEI, MYOU, aka(rui), a(keru) - bright

肺  HAI - lung

b) 早 -> 古 -> 員 -> 販  

早  SOU, SA, haya(i) , haya(meru) - early, fast, hasten

古  KO, furu(i) - old

員  IN - member

販  HAN - sell