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

Which of the following phyla consists exclusively of marine animals?

Water vascular system is the characteristic of which group of the following:
$(a)$ Porifera $(b)$ Ctenophora $(c)$ Echinodermata $(d)$ Chordata

These animals exhibit bilateral symmetry in the larval stage and radial symmetry in the adult stage.

Echinodermata is a group of animals which are

The perforated plate located at the aboral end of a starfish is known as: