Q.150 Zoology ⭐ 360° Option Elimination Active
NEET 2026 Zoology Question 150 Solution
Topic: Breathing and Exchange of Gases · Official NTA Booklet Code 50
Question
Sponges exchange O₂ with CO₂ by
✓
Verified Against NTA Final Answer Key
Option (1) : simple diffusion over their entire body surfaces
📚 Breathing and Exchange of Gases Easy
📋 Given Parameters & Problem Setup
Organism Group Sponges (Phylum Porifera)
Physiological Process Gas exchange (O₂ with CO₂)
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⏱️ Save ~40 seconds The 30-Second Exam Hall Shortcut: ⚡ Simple Diffusion in Lower Invertebrates
Sponges, Coelenterates, Flatworms lack specialized organs -> Simple Diffusion over entire body surface!
1 Recall respiratory adaptations across animal phyla in NCERT Breathing and Exchange of Gases:
2 Sponges, coelenterates, flatworms: Simple diffusion over entire body surface.
3 Earthworms: Moist cuticle (cutaneous).
4 Insects: Tracheal tubes.
5 Aquatic arthropods, molluscs, fish: Gills (branchial).
6 Sponges exchange gases via simple diffusion over entire body surface.
7 Option (1) is the exact match. Mark Option (1) in under 3 seconds!
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Why You Can 100% Trust This Shortcut: NCERT Biology · Breathing and Exchange of Gases (Respiratory Volumes: Functional Residual Capacity FRC = ERV + RV).
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Step-by-Step Rigorous Workflow & Mathematical Proof
Step 1
Respiratory Adaptations in Lower Invertebrates
Mechanisms of breathing vary among different groups of animals depending on their habitats and levels of organization. Lower invertebrates like sponges (Porifera), coelenterates (Cnidaria), and flatworms (Platyhelminthes) exhibit cellular or tissue levels of organization and lack specialized vascular or respiratory organs.
- • Water canal system circulates water past choanocytes and pinacocytes for direct gas exchange.
Step 2
Compare with Higher Invertebrate Respiratory Organs
Earthworms use their moist cuticle (cutaneous respiration, Option 2). Insects have a network of tracheal tubes to transport atmospheric air within the body (Option 3). Aquatic arthropods, molluscs, and fishes use specialized vascularized structures called gills (branchial respiration, Option 4).
- • Option (1) is uniquely correct for sponges.
Step 3
Conclusion
Sponges exchange O₂ with CO₂ by simple diffusion across their entire body surfaces.
- • Matches official NTA final answer key Option A / (1).
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4-Option Deep Scan
360° Option Elimination Engine Key Feature
Diagnose every choice: Know exactly why the right option works and why distractors fail.
1 A
✓ 100% Correct Verdict & Scientific Reason:
100% accurate. Canonical NCERT mechanism of respiratory gas exchange in Porifera.
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Why this is airtight: None; direct textbook recall.
2 B
✗ Incorrect Verdict & Scientific Reason:
Incorrect. Cutaneous respiration using moist cuticle is characteristic of annelids (earthworms) and amphibians (frogs).
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Student Fallacy (Why candidates pick this trap): Confusing earthworm cutaneous respiration with sponge surface diffusion.
3 C
✗ Incorrect Verdict & Scientific Reason:
Incorrect. Tracheal respiratory systems are found in terrestrial arthropods (insects, centipedes).
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Student Fallacy (Why candidates pick this trap): Confusing insect tracheal networks with sponge body surfaces.
4 D
✗ Incorrect Verdict & Scientific Reason:
Incorrect. Branchial respiration via gills occurs in crustaceans, molluscs, and fishes.
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Student Fallacy (Why candidates pick this trap): Assuming all aquatic organisms use gills.
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NTA Trap Alert: Assuming All Aquatic Creatures Have Gills
Students often generalize: "Sponges live in water, so they must use gills." Gills require complex tissues and circulatory capillaries. Sponges have simple cellular-grade organization and rely entirely on simple diffusion.
🛡️ How to avoid the -1 mark: Remember: Sponges are simple; simple animals use SIMPLE diffusion!
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Core NEET Syllabus Standard
NEET Biology Core Syllabus · Breathing and Exchange of Gases Standard Benchmark
Core Scientific Principle Tested:
"Lower invertebrates like sponges exchange O₂ and CO₂ by simple diffusion across their entire body surfaces facilitated by the water canal system."
Syllabus Focus: Respiratory Organs
✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗
Sponges are Simple: Simple Diffusion washes through every cell and pore!
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