OESOPHAGUS STOMACH
ECHINODERMS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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True
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False
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Either A or B
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None of the above
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Detailed explanation-1: -Echinodermata: Systematics. In traditional taxonomy, there are five classes of living echinoderms: Crinoidea (sea lilies), Asteroidea (starfish), Ophiuroidea (brittle stars or snake stars), Echinoidea (sea urchins and sand dollars), and Holothuroidea (sea cucumbers).
Detailed explanation-2: -The correct answer is (b). Echinoderms do not have gills.
Detailed explanation-3: -Examples of echinoderms include sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars (Fig. 3.83). Although they may appear very different, echinoderms all have two major defining characteristics that set them apart from all other animals: a water vascular system and five-sided radial symmetry.
Detailed explanation-4: -Echinoderms have spiny skin. Unio is a mollusc. So, the correct answer is option D.