In all pairs except (b), first is the animal and second is the class of the animal to which is belongs.

In all pairs except (c), second is the related to first.

In all pairs except (a), first is the insect and second is the thing which is damaged by the insect.

In all pairs except (c), both the words belong to same class.

In all pairs except (d) , first is an alloy and second is thing which is made by that alloy. And iron is a metal not alloy.

In all pairs except (d), Second is the name of the foot of first.

In all pairs expect (d), first required for second to use.

In all except (c), second is attached with first.

In all pairs expect (c), first is know as the collection of second.

In all pairs expert (c), first is the wastage of second.