OESOPHAGUS STOMACH
ECHINODERMS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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their larvae are bilaterally symmetrical.
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they have decentralized nervous systems.
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most species have no head.
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all of the above
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Detailed explanation-1: -Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development.
Detailed explanation-2: -Both Echinodermata and Chordata are closely related as they are included in deuterostomes because both show bilateral symmetry in any stage of the life cycle.
Detailed explanation-3: -Echinoderms have a spiny endoskeleton. They have radial symmetry as adults but bilateral symmetry as larvae. Echinoderms have a unique water vascular system with tube feet.
Detailed explanation-4: -In larval stage bilateral symmetry is present in Echinodermata.