What is the body wall of Echinoderms composed of?

Match the following columns:

Column-$I$ (Animal)	Column-$II$ (Genus)
$P$. Starfish	$I$. Antedon
$Q$. Sea urchin	$II$. Echinus
$R$. Sea lily	$III$. Cucumaria
$S$. Sea cucumber	$IV$. Asterias
$T$. Brittle star	$V$. Ophiura

What type of body symmetry do Echinoderms exhibit?

Aristotle's lantern is found in .........

Assertion : Ambulacral system plays a major role in locomotion of echinoderm.
Reason : Hydraulic pressure of fluid and contraction of muscle of tube feet make possible movement of echinoderm.

Which phylum consists of animals that are free-swimming in the larval stage and sessile (attached to a substrate) in the adult stage?