Which feature is common among leech,cockroach,and scorpion?

Match the following columns:

Column-$I$	Column-$II$
$I.$ Skin without scales	$p.$ $Catla$
$II.$ Placoid scales	$q.$ $Hagfish$
$III.$ Cycloid scales	$r.$ $Chameleon$
$IV.$ Epidermal scales	$s.$ $Ray-fish$

Define the following terms:
$(i)$ Poikilothermous
$(ii)$ Homoiothermous

Write one example for each of the following in the space provided:
$(a)$ Cold-blooded animal.
$(b)$ Warm-blooded animal.
$(c)$ Animal possessing dry and cornified skin.
$(d)$ Dioecious animal.

In which of the following sets,are the groups not correctly matched phylum-wise?

Which of the following is not a parasitic adaptation?