Bipinnaria is the larva of

Echinoderms are headless,brainless,and heartless. Yet,they are placed at the top of invertebrates because of the presence of:

The main function of pedicellariae in $Asterias$ is:

An animal that transforms from bilateral to radial symmetry in its life history is

Which of the following options have features corresponding to the given animals?
$Aplysia$, $Asterias$, $Antedon$, $Echinus$

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.