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#echinoderms

22 public questions tagged with this topic.

ZOOLOGY

Why do echinoderms exhibit bilateral symmetry in their larval stage but radial symmetry as adults?

Larval Stage: Bilateral symmetry enables free-swimming larvae to balance and move efficiently in open water. Adult Stage: Adult echinoderms live on the seafloor (benthic zone). Pentaradial symmetry allows them to feed and detect surroundings equally from all directions.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

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ZOOLOGY

Which of the following features is incorrect regarding echinoderms?

Echinoderms do not have a closed circulatory system; they rely on their water vascular system for circulation. This follows from NCERT principle where relation explains outcome clearly for students.

Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function, Topic: Structural organization and physiology.

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