What is true about $Nereis$,scorpion,cockroach,and silver fish?

Which one feature is common to leech,cockroach and scorpion?

In which aspects do organisms of the animal kingdom show diversity?

Give the names of the following:
$(a)$ $A$ limbless animal
$(b)$ $A$ cold-blooded animal
$(c)$ $A$ warm-blooded animal
$(d)$ An animal possessing dry and cornified skin
$(e)$ An animal having a canal system and spicules
$(f)$ An animal with cnidoblasts

The term "phylum" in animal classification was coined by

Select the incorrect option with respect to the features present in the three phyla: Arthropoda,Mollusca,and Chordata.