Which of the following is a correctly matched pair?

Given are the four matches of phyla with their characteristic cells:
$A$. Coelenterata - Nematocytes
$B$. Porifera - Choanocytes
$C$. Ctenophora - Solenocytes
$D$. Platyhelminthes - Nephrocytes
Mark the option that has both correct matches.

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

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Contractile vacuole	$(i)$ Excretory unit
$(b)$ Parapodia	$(ii)$ Food ingestion
$(c)$ Flame cells	$(iii)$ Locomotion
$(d)$ Nematocysts	$(iv)$ Osmoregulation

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

Which one of the following phyla is correctly matched with its two general characteristics?