OESOPHAGUS STOMACH
ECHINODERMS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Echinoidea, no arms, ball or disk shape
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Holothuroidea, elongated body, tentacles around the mouth
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Ophiuroidea, long thin legs, single organ set in central disk
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Crinoidea, upward-facing mouth, long feather-like arms
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Detailed explanation-1: -Feather stars are in the class Crinoidea, which is a group of echinoderms that includes sea lilies and feather stars.
Detailed explanation-2: -crinoid, any marine invertebrate of the class Crinoidea (phylum Echinodermata) usually possessing a somewhat cup-shaped body and five or more flexible and active arms. The arms, edged with feathery projections (pinnules), contain the reproductive organs and carry numerous tube feet with sensory functions.
Detailed explanation-3: -Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid order, Comatulida.
Detailed explanation-4: -The tegmen is located on the dorsal region of the cup, surrounded by the upward reaching feeding arms. The mouth is strategically positioned at the base of the feeding arms which use their ciliated ambulacral grooves to transport the collected food particles down the arms to the mouth.