Answer:
a) 篤 -> 駐 -> 素 -> 納
篤 TOKU - serious, cordial
駐 CHUU - stop, reside
素 SO, SU - element, naked, simple
納 NOU, TOU, NA, NAN, osa(meru) - pay, supply, accept, store
b) 警 -> 詳 -> 養 -> 飲
警 KEI - admonish, warn
詳 SHOU, kuwa(shii) - detailed, full, familiar with
養 YOU, yashina(u) - rear, support, adopt
飲 IN, no(mu) - drink