Answer:
a) 動 -> 加 -> 員 -> 販
動 DOU , ugo(ku) - move
加 KA, kuwa(eru), kuwa(waru) - add, append, join, take part
員 IN - member
販 HAN - sell
b) 針 -> 古 -> 員 -> 賦
針 SHIN, hari - needle
古 KO, furu(i) - old
員 IN - member
賦 FU - tribute, payment, installment