Which of the following statements is false?

Fill in the blanks marked in the classification table of $Vertebrata$ from the choices provided below with respect to $A, B, C, D, E$ and $F$ and choose the correct option:
$I$. Pisces
$II$. Osteichthyes
$III$. Agnatha
$IV$. Gnathostomata
$V$. Chondrichthyes
$VI$. Cyclostomata
$A - B - C - D - E - F$

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Amphibia	$(1)$ Air bladder
$(b)$ Mammalia	$(2)$ Cartilaginous notochord
$(c)$ Chondrichthyes	$(3)$ Mammary gland
$(d)$ Osteichthyes	$(4)$ Pneumatic bones
$(e)$ Cyclostomata	$(5)$ Dual habitat
$(f)$ Aves	$(6)$ Jawless,circular,sucking mouth

Find the mismatched pair regarding the exoskeleton.

Which of the following statements are true/false?
$(i)$ In $Torpedo$,the electric organs are capable of generating strong electric shock to paralyze the prey.
$(ii)$ Bony fishes use pectoral,pelvic,dorsal,anal,and caudal fins in swimming.
$(iii)$ Amphibian skin is moist and has thick scales.
$(iv)$ Birds are poikilothermic animals.
$(v)$ The most unique mammalian characteristic is the presence of milk-producing mammary glands by which the young ones are nourished.

Identify the categories $P$,$Q$,and $R$ in the given classification chart of Vertebrata.