Which of the Following Animal Groups is Entirely Aquatic

Question

Which of the following animal groups is entirely aquatic?
A)Mollusca
B)Crustacea
C)Echinodermata
D)Nematoda
E)Platyhelminthes

Accepted Answer

Echinoderms, such as starfish, sea urchins, and sea cucumbers, are exclusively marine animals and do not have any freshwater or terrestrial representatives.