Answer:
a) 要 -> 妙 -> 省 -> 眺
要 YOU, i(ru) - essential(s) need
妙 MYOU - strange, odd, adroit, mystery
省 SEI, SHOU, kaerimiru, habu(ku) - ministry, reflect, omit
眺 CHOU, naga(meru) - look at, watch, gaze
b) 吉 -> 呈 -> 理 -> 黒
吉 KICHI, KITSU, yoshi - good luck
呈 TEI - offer, present, exhibit
理 RI - reason, logic
黒 KOKU, kuro(i) - black