Q.167 Zoology ⭐ 360° Option Elimination Active

NEET 2021 Zoology Question 167 Solution

Topic: Animal Kingdom · Official NTA Booklet Code M1

Question

Match the following: (a) Physalia (i) Pearl oyster (b) Limulus (ii) Portuguese Man of War (c) Ancylostoma (iii) Living fossil (d) Pinctada (iv) Hookworm List - I List - II Choose the correct answer from the options given below. (a) (b) (c) (d)

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

✓

Verified Against NTA Final Answer Key

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

📚 Animal Kingdom Easy

📋 Given Parameters & Problem Setup

List I (Scientific Names) (a) Physalia, (b) Limulus, (c) Ancylostoma, (d) Pinctada

List II (Common Names / Attributes) (i) Pearl oyster, (ii) Portuguese Man of War, (iii) Living fossil, (iv) Hookworm

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The 30-Second Exam Hall Shortcut: ⚡ "Physalia = Portuguese Man of War, Limulus = Living Fossil Arthropod"

⏱️ Save ~30 seconds

Physalia is Portuguese Man of War ((a)-(ii)) and Limulus is the living fossil King Crab ((b)-(iii)). Looking at options, only Option (3) has (a)-(ii) and (b)-(iii)! Solved in 10 seconds.

1 Match (a) Physalia (Cnidaria) -> (ii) Portuguese Man of War.

2 Inspect options: Option (1) has (a)-(ii), (b)-(iii), but (c)-(i). Option (3) has (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i).

3 Verify (c) Ancylostoma (Aschelminthes) -> (iv) Hookworm.

4 Verify (d) Pinctada (Mollusca) -> (i) Pearl oyster.

5 Confirm Option (3).

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Animal Kingdom (Phylum Cnidaria: Physalia - Portuguese man-of-war; Phylum Arthropoda: Limulus - King crab, living fossil; Phylum Aschelminthes: Ancylostoma - Hookworm; Phylum Mollusca: Pinctada - Pearl oyster).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Taxonomic Assignment of Genera to Phyla and Common Names

Each genus listed is a classic NCERT type specimen representing distinct invertebrate phyla: - (a) *Physalia* (Phylum Coelenterata / Cnidaria): Colonial siphonophore possessing gas-filled pneumatophore float resembling an 18th-century warship, commonly called Portuguese Man of War. - (b) *Limulus* (Phylum Arthropoda): Commonly known as the King crab or horseshoe crab. Having remained virtually unchanged over hundreds of millions of years, it is universally designated a Living fossil. - (c) *Ancylostoma* (Phylum Aschelminthes): Intestinal nematode parasite commonly named the Hookworm. - (d) *Pinctada* (Phylum Mollusca): Bivalve mollusc commercially cultured for natural and cultured nacre pearls, commonly termed the Pearl oyster.

\begin{aligned} \text{Physalia} &\iff \text{Portuguese Man of War} \quad [\text{(a)} \to \text{(ii)}] \\ \text{Limulus} &\iff \text{Living fossil} \quad [\text{(b)} \to \text{(iii)}] \\ \text{Ancylostoma} &\iff \text{Hookworm} \quad [\text{(c)} \to \text{(iv)}] \\ \text{Pinctada} &\iff \text{Pearl oyster} \quad [\text{(d)} \to \text{(i)}] \end{aligned}

Step 2

Compilation and Option Verification

Matching sequence: (a) -> (ii), (b) -> (iii), (c) -> (iv), (d) -> (i). This corresponds uniquely and unambiguously 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 because Ancylostoma is a hookworm (iv), not pearl oyster (i), and Pinctada is pearl oyster (i), not hookworm (iv).

⚠️

Student Fallacy (Why candidates pick this trap): Swapping the pairs for Ancylostoma and Pinctada.

2 2

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Assigns hookworm to Physalia and pearl oyster to Limulus.

⚠️

Student Fallacy (Why candidates pick this trap): Gross misalignment of phyla.

3 3

✓ 100% Correct

Verdict & Scientific Reason:

Correct. Perfectly matches all four genera to their textbook common designations.

💡

Why this is airtight: None. Candidate accurately recalls standard zoological nomenclature.

4 4

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Misidentifies Physalia as pearl oyster and Limulus as hookworm.

⚠️

Student Fallacy (Why candidates pick this trap): Random guessing without recalling phylum examples.

⚠️

NTA Trap Alert: Inverted Matching Trap (c) vs (d)

Option 1 and Option 3 share the first two matches ((a)-(ii), (b)-(iii)). Careless candidates stop reading after the first two items and erroneously bubble Option 1.

🛡️ How to avoid the -1 mark: Always cross-check all 4 column pairs before finalizing the answer.

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Core NEET Syllabus Standard

NEET / NCERT Biology · Animal Kingdom Standard Benchmark

Core Scientific Principle Tested:

"Physalia is Portuguese man-of-war, Limulus is a living fossil, Ancylostoma is hookworm, and Pinctada is pearl oyster."

Syllabus Focus: Classification of Non-Chordates

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2021 Zoology Question 167 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ "Physalia = Portuguese Man of War, Limulus = Living Fossil Arthropod"

Step-by-Step Rigorous Workflow & Mathematical Proof

Taxonomic Assignment of Genera to Phyla and Common Names

Compilation and Option Verification

360° Option Elimination Engine Key Feature

NTA Trap Alert: Inverted Matching Trap (c) vs (d)

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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