2448. What characters can be added here so that each character contains a part of the previous character? a) 早 -> _ -> _ -> 増 b) 畑 -> _ -> _ -> 惑

a) 早 -> 古 -> 吐 -> 増  

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

古  KO, furu(i) - old

吐  TOU, ha(ku) - spew, vomit, give vent to

増  ZOU, ma(su), fu(eru), fu(yasu) - increase, rise, raise

b) 畑 -> 里 -> 域 -> 惑  

畑  hatake - cultivated field

里  RI, sato - village

域  IKI - region, area

惑  WAKU, mado(u) - go astray, be tempted