Hard calcium carbonate structures are used as skeleton by
(a) Echinodermata
(b) Protochordata
(c) Arthropoda
(d) Nematoda
Correct Answer: (a) Echinodermata
Explanation:
Hard calcium carbonate structures are used as skeletons by Echinodermata.
Echinodermata are exclusively marine species. Examples are marine stars, sea cucumbers, sea urchins, and brittle stars.
The body of an adult organism is radially symmetrical, usually pentamerous.
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