Question Video: Identifying the Organism that Belongs to the Phylum Echinodermata | Nagwa Question Video: Identifying the Organism that Belongs to the Phylum Echinodermata | Nagwa

Question Video: Identifying the Organism that Belongs to the Phylum Echinodermata Biology • First Year of Secondary School

Which of the following organisms belongs to the phylum Echinodermata? [A] Oyster [B] Starfish [C] Octopus [D] Snail

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Video Transcript

Which of the following organisms belongs to the phylum Echinodermata? (A) Oyster, (B) starfish, (C) octopus, or (D) snail.

Organisms that belong to the phylum Echinodermata have an unsegmented and radially symmetrical body, meaning that it is in one piece. And it is the same on both sides and top and bottom. They also have a hard endoskeleton, or inner skeleton, surrounded by an epidermidis, or skin.

Let’s determine which of these answer choices falls into this category. Oysters, snails, and octopuses belong to the phylum Mollusca. Organisms that belong to this phylum secrete a hard shell, among other common characteristics. In addition, they do not have endoskeletons. So they cannot be classified as echinoderms. Therefore, we can eliminate answers (A), (C), and (D).

Starfish do have unsegmented, radially symmetrical bodies and a hard skeleton surrounded by an epidermidis. So the correct answer is (B). Starfish belong to the phylum Echinodermata.

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