Select the odd one out:

Identify the correct terms for the following analogy-based questions:
$(i)$ Porifera : Choanocytes :: Platyhelminthes : ....
$(ii)$ Chondrichthyes : Placoid scales :: Osteichthyes : ....

Which one of the following is not correctly matched?

What is the exoskeleton of fish made of?

Column $-I$ represents the phylum and Column $-II$ represents the larval stage. Select the correct option:

Column $-I$	Column $-II$
$(A)$ Porifera	$(i)$ Tornaria larva
$(B)$ Hemichordata	$(ii)$ Free-swimming larva
$(C)$ Cnidaria	$(iii)$ Parenchymula larva
$(D)$ Echinodermata	$(iv)$ Planula larva

Which two phyla of animals exhibit metamerism (segmentation)?