Identify the animals given below.

In Mollusca, excretion occurs through $......$ and in Hemichordata, it occurs through $......$.

$A$ list of animals is given below. Identify the animals with an open circulatory system and choose the correct answer.
$(A)$ Ascidia $(B)$ Cockroach
$(C)$ Earthworm $(D)$ Prawn
$(E)$ Silverfish $(F)$ Snail
$(G)$ Squid

Which statement is true for $Spongilla$,$Leech$,$Dolphin$,and $Penguin$?

Choose the correct pair:

Differentiate between Chondrichthyes and Osteichthyes.