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Q.37 Botany ⭐ 360° Option Elimination Active
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NEET 2020 Botany Question 37 Solution

Topic: Animal Kingdom · Official NTA Booklet Code E1
NEET 2020 Botany Question 37: Vertebrate Classes: Diagnostic Characters of Cyclostomes, Chondrichthyes & Osteichthyes

Question

Match the following columns and select the correct option. Column - I Column - II (a) 6 - 15 pairs of (i) Trygon gill slits (b) Heterocercal (ii) Cyclostomes caudal fin (c) Air Bladder (iii) Chondrichthyes (d) Poison sting (iv) Osteichthyes (a) (b) (c) (d)

  1. (1)(ii) (iii) (iv) (i)
  2. (2)(iii) (iv) (i) (ii)
  3. (3)(iv) (ii) (iii) (i)
  4. (4)(i) (iv) (iii) (ii)
✓
Verified Against NTA Final Answer Key
Option (1) : (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
📚 Animal Kingdom Easy
📋 Given Parameters & Problem Setup
Column I (Traits) (a) 6-15 pairs gill slits, (b) Heterocercal caudal fin, (c) Air bladder, (d) Poison sting
Column II (Taxa) (i) Trygon, (ii) Cyclostomes, (iii) Chondrichthyes, (iv) Osteichthyes
⚡

The 30-Second Exam Hall Shortcut: ⚡ "Cyclo = 6-15 Gill Slits; Trygon = Poison Sting"

⏱️ 35 seconds

Cyclostomes are characterized by 6-15 pairs of gill slits (a->ii). Trygon is the stingray with a poison sting (d->i). Chondrichthyes have heterocercal fins (b->iii). Osteichthyes possess air bladders for buoyancy (c->iv). Match gives Option (1) in 10 seconds!

1 Match (a) 6-15 pairs of gill slits -> (ii) Cyclostomes.
2 Match (d) Poison sting -> (i) Trygon (stingray).
3 Match (c) Air bladder -> (iv) Osteichthyes (bony fishes).
4 Match (b) Heterocercal caudal fin -> (iii) Chondrichthyes.
5 Resulting combination: (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i) -> Option 1.
🛡️
Why You Can 100% Trust This Shortcut: NCERT Biology · Animal Kingdom (Vertebrata: Cyclostomata, Chondrichthyes, Osteichthyes)
📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Match 6-15 Pairs of Gill Slits

Class Cyclostomata includes jawless living vertebrates (e.g., Petromyzon, Myxine) that possess an elongated body bearing 6 to 15 pairs of gill slits for respiration. Thus, (a) matches (ii).

Step 2

Match Heterocercal Caudal Fin

Class Chondrichthyes (cartilaginous fishes like Scoliodon) possess an asymmetrical heterocercal caudal fin where the vertebral column extends into the larger dorsal lobe. Thus, (b) matches (iii).

Step 3

Match Air Bladder

Class Osteichthyes (bony fishes like Exocoetus, Labeo, Betta) possess an air bladder (swim bladder) which regulates buoyancy, preventing them from sinking. Thus, (c) matches (iv).

Step 4

Match Poison Sting

Trygon (sting ray) is a cartilaginous fish that possesses a venomous serrated spine (poison sting) on its whip-like tail for defense. Thus, (d) matches (i).

⭐

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 A
✓ 100% Correct
Verdict & Scientific Reason:

Accurate pairing across all four diagnostic vertebrate features.

💡
Why this is airtight: None; canonical chordate classification.
2 B
✗ Incorrect
Verdict & Scientific Reason:

Incorrect; Chondrichthyes have 5-7 pairs of gill slits without operculum, not 6-15 pairs.

⚠️
Student Fallacy (Why candidates pick this trap): Confusing cartilaginous fish gill numbers with cyclostome gill slits.
3 C
✗ Incorrect
Verdict & Scientific Reason:

Incorrect; Osteichthyes have 4 pairs of gill slits with opercula, not 6-15 pairs.

⚠️
Student Fallacy (Why candidates pick this trap): Misassigning bony fish traits to cyclostomes.
4 D
✗ Incorrect
Verdict & Scientific Reason:

Incorrect; Trygon is a specific organism with a poison sting, not a taxon with 6-15 gill slits.

⚠️
Student Fallacy (Why candidates pick this trap): Mismatching species name with anatomical character.
⚠️

NTA Trap Alert: Torpedo vs Trygon Distinction

Both are Chondrichthyes, but Torpedo possesses ELECTRIC ORGANS, while Trygon possesses a POISON STING.

🛡️ How to avoid the -1 mark: Mnemonic: "Tor-pedo gives a Shock (Electric); Try-gon Stings your toe (Poison sting)!"
📖

Core NEET Syllabus Standard

Botany · Animal Kingdom Standard Benchmark
Core Scientific Principle Tested:

""

Syllabus Focus: Vertebrate Classes: Diagnostic Characters of Cyclostomes, Chondrichthyes & Osteichthyes
✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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