2718. What characters can be added here so that each character contains a part of the previous character? a) 切 -> _ -> _ -> 増 b) 章 -> _ -> _ -> 地

a) 切 -> 召 -> 吐 -> 増  

切  SETSU, ki(ru), ki(reru) - cut

召  SHOU, me(su) - summon, wear, take

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

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

b) 章 -> 古 -> 吐 -> 地  

章  SHOU - chapter, badge, mark

古  KO, furu(i) - old

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

地  CHI, JI - earth, land