Mark the odd member from the following:

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 group of animals belong to the same phylum?

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

Match the following columns and select the correct option.
Column $-I$ | Column $-II$
$(a)$ $6-15$ pairs of gill slits | $(i)$ Trygon
$(b)$ Heterocercal caudal fin | $(ii)$ Cyclostomes
$(c)$ Air Bladder | $(iii)$ Chondrichthyes
$(d)$ Poison sting | $(iv)$ Osteichthyes

Match the following list of animals with their level of organisation and choose the correct sequence.

Column $I$	Column $II$
$A$. Organ level	$p$. Pheretima
$B$. Cellular aggregate level	$q$. Fasciola
$C$. Tissue level	$r$. Spongilla
$D$. Organ system level	$s$. Obelia