Q.153 Zoology ⭐ 360° Option Elimination Active

NEET 2021 Zoology Question 153 Solution

Topic: Animal Kingdom · Official NTA Booklet Code M1

Question

Match List - I with List - II. (a) Metamerism (i) Coelenterata (b) Canal system (ii) Ctenophora (c) Comb plates (iii) Annelida (d) Cnidoblasts (iv) Porifera List - I List - II Choose the correct answer from the options given below. (a) (b) (c) (d)

(1)(iv) (iii) (i) (ii)
(2)(iii) (iv) (i) (ii)
(3)(iii) (iv) (ii) (i)
(4)(iv) (i) (ii) (iii)

✓

Verified Against NTA Final Answer Key

Option (3) : (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)

📚 Animal Kingdom Easy

📋 Given Parameters & Problem Setup

List-I (Features) (a) Metamerism, (b) Canal system, (c) Comb plates, (d) Cnidoblasts

List-II (Phyla) (i) Coelenterata, (ii) Ctenophora, (iii) Annelida, (iv) Porifera

⚡

The 30-Second Exam Hall Shortcut: ⚡ "Match Comb Plates to Ctenophora & Cnidoblasts to Coelenterata"

⏱️ Save ~30 seconds

Comb plates (8 ciliated rows) are unique to Ctenophora ((c) → (ii)), and Cnidoblasts/stinging cells define Coelenterata ((d) → (i)). Metamerism is the hallmark of Annelida ((a) → (iii)), and the canal/water transport system is diagnostic of Porifera ((b) → (iv)). This yields (iii), (iv), (ii), (i) → Option (3) instantly!

1 Match Metamerism (true segmentation) → Annelida (iii).

2 Match Canal system (water transport via ostia, spongocoel, osculum) → Porifera (iv).

3 Match Comb plates (8 external rows for locomotion) → Ctenophora (ii).

4 Match Cnidoblasts (stinging capsules/nematocysts) → Coelenterata (i).

5 Identify row: (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i) → Option (3).

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Animal Kingdom (Diagnostic phylum features: Annelida = metamerism, Porifera = canal system, Ctenophora = comb plates, Coelenterata = cnidoblasts).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Analysis of Invertebrate Phylum Hallmarks

Each invertebrate phylum possesses defining anatomical synapomorphies: - (a) Metamerism: True internal and external segmented body organization with serial repetition of organs, characteristic of Annelida (e.g., earthworm, Nereis). - (b) Canal system: Sponges possess a water transport or canal system where water enters through microscopic pores (*ostia*) into a central cavity (*spongocoel*), driven by flagellated choanocytes, exiting via the *osculum*; diagnostic of Porifera. - (c) Comb plates: Ctenophores (comb jellies/sea walnuts) bear eight external rows of ciliated comb plates that function exclusively in locomotion; diagnostic of Ctenophora. - (d) Cnidoblasts (cnidocytes): Specialized defensive and prey-capturing cells containing stinging capsules (*nematocysts*); characteristic of Coelenterata / Cnidaria.

\begin{aligned} \text{(a) Metamerism} & \longrightarrow \text{(iii) Annelida} \\[3pt] \text{(b) Canal system} & \longrightarrow \text{(iv) Porifera} \\[3pt] \text{(c) Comb plates} & \longrightarrow \text{(ii) Ctenophora} \\[3pt] \text{(d) Cnidoblasts} & \longrightarrow \text{(i) Coelenterata} \end{aligned}

Step 2

Option Combination Verification

Comparing the mapped matrix with the given choices confirms: (a) $\rightarrow$ (iii) (b) $\rightarrow$ (iv) (c) $\rightarrow$ (ii) (d) $\rightarrow$ (i) This perfectly corresponds to Option (3).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 1

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Mismatches Metamerism to Porifera and Canal system to Annelida.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing the canal system of sponges with the closed circulatory system or nephridial canals of annelids.

2 2

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Inverts Comb plates (assigned to Coelenterata) and Cnidoblasts (assigned to Ctenophora).

⚠️

Student Fallacy (Why candidates pick this trap): Swapping Ctenophores and Cnidarians because both share diploblastic tissue-level organization and acellular mesoglea.

3 3

✓ 100% Correct

Verdict & Scientific Reason:

Correct. Perfectly matches metamerism to Annelida, canal system to Porifera, comb plates to Ctenophora, and cnidoblasts to Coelenterata.

💡

Why this is airtight: None. This is the canonical NCERT mapping.

4 4

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Assigns metamerism to Porifera and cnidoblasts to Annelida.

⚠️

Student Fallacy (Why candidates pick this trap): Gross misidentification of fundamental phylum traits across divergent clades.

⚠️

NTA Trap Alert: Water Canal System vs Water Vascular System Confusion

Aspirants often confuse the water canal system of Porifera (feeding, respiration, excretion) with the water vascular (ambulacral) system of Echinodermata (locomotion, food capture).

🛡️ How to avoid the -1 mark: Sponges have a "Water Canal System"; Starfishes/Echinoderms have a "Water Vascular System".

📖

Core NEET Syllabus Standard

NEET / NCERT Biology · Animal Kingdom Standard Benchmark

Core Scientific Principle Tested:

"Metamerism characterizes Annelida; choanocyte canal system characterizes Porifera; ciliated comb plates characterize Ctenophora; cnidocytes characterize Cnidaria."

Syllabus Focus: Salient Features of Non-Chordate Phyla

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2021 Zoology Question 153 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ "Match Comb Plates to Ctenophora & Cnidoblasts to Coelenterata"

Step-by-Step Rigorous Workflow & Mathematical Proof

Analysis of Invertebrate Phylum Hallmarks

Option Combination Verification

360° Option Elimination Engine Key Feature

NTA Trap Alert: Water Canal System vs Water Vascular System Confusion

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Animal Kingdom

Basis of Classification - Body Symmetry in Echinodermata

Class Reptilia - Locomotion and Heart Chamber Exceptions

Fundamental Diagnostic Characteristics of Phylum Chordata

Coelom Types and Mesodermal Linings (Pseudocoelomate)

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