OESOPHAGUS STOMACH
ECHINODERMS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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are radially symmetrical as larvae and as adults.
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have an exoskeleton as adults.
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are bilaterally symmetrical as larvae and radially symmetrical as adults.
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are radially symmetrical as larvae and bilaterally symmetrical as adults.
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Detailed explanation-1: -Echinodermata includes marine animals which have spiny body surface and calcareous exoskeleton. They are triploblastic coelomates. They are radially symmetrical in adult stage but shows bilateral symmetry in the larval stage.
Detailed explanation-2: -In phylum Echinodermata, adults are radially symmetrical, as in starfish. But their larvae are bilaterally symmetrical.
Detailed explanation-3: -Echinoderms have a spiny endoskeleton. They have radial symmetry as adults but bilateral symmetry as larvae.
Detailed explanation-4: -Although the echinoderms show both radial and bilateral symmetry in their life cycle, they are classified as bilaterally symmetric and not radially symmetric because they are evolved from bilaterally symmetrical organisms.
Detailed explanation-5: -Echinoderms evolved from animals with bilateral symmetry. Although adult echinoderms possess pentaradial symmetry, their larvae are ciliated, free-swimming organisms with bilateral symmetry.