Q.160 Zoology ⭐ 360° Option Elimination Active

NEET 2023 Zoology Question 160 Solution

Topic: Excretory Products and their Elimination · Official NTA Booklet Code G5

Question

Given below are statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Nephrons are of two types: Cortical & Juxta medullary, based on their relative position in cortex and medulla. Reason R: Juxta medullary nephrons have short loop of Henle whereas, cortical nephrons have longer loop of Henle. In the light of the above statements, choose the correct answer from the options given below:

(1)A is false but R is true.
(2)Both A and R are true and R is the correct explanation of A.
(3)Both A and R are true but R is NOT the correct explanation of A.
(4)A is true but R is false.

✓

Verified Against NTA Final Answer Key

Option (4) : A is true but R is false.

📚 Excretory Products and their Elimination Medium

📋 Given Parameters & Problem Setup

Assertion (A) Nephrons are of two types: Cortical & Juxtamedullary based on relative position in cortex and medulla.

Reason (R) Juxtamedullary nephrons have short loop of Henle whereas cortical nephrons have longer loop of Henle.

⚡

The 30-Second Exam Hall Shortcut: ⚡ Henle Loop Inversion Alert: Juxtamedullary has LONG Loop!

⏱️ Save ~25 seconds

Assertion is TRUE (cortical & juxtamedullary based on position). But Reason claims juxtamedullary nephrons have short loops! In reality, Juxtamedullary nephrons have very LONG loops running deep into the medulla to concentrate urine! Reason is completely FALSE! Select Option (4)!

1 Check Assertion A: Nephrons are categorized into cortical and juxtamedullary based on location -> True.

2 Check Reason R: Claims juxtamedullary have short loops and cortical have long loops -> Completely reversed! (Cortical = short loop; Juxtamedullary = long loop) -> Reason is False.

3 Assertion is true but Reason is false.

4 Match Option (4) A is true but R is false.

🛡️

Why You Can 100% Trust This Shortcut: Canonical NCERT Human Physiology nephron architecture and counter-current concentrating anatomy.

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluation of Assertion A (Nephron Types)

Nephrons are anatomically classified according to the depth of their renal corpuscles and extent of their loops within the kidney zones:

\text{Nephron Types} = \begin{cases} \mathbf{\text{Cortical (}\approx 85\%\text{):}} & \text{Glomerulus in outer cortex} \\[3pt] \mathbf{\text{Juxtamedullary (}\approx 15\%\text{):}} & \text{Glomerulus at cortex-medulla junction} \end{cases} \implies \text{Assertion is } \mathbf{\text{TRUE}}

Step 2

Evaluation of Reason R (Henle's Loop Dimensions)

The length of the loop of Henle differs sharply between the two classes:

\begin{aligned} \text{\textbf{Cortical Nephrons:}} & \quad \mathbf{\text{Short loop of Henle}} \text{ (extends very little into medulla)} \\[4pt] \text{\textbf{Juxtamedullary Nephrons:}} & \quad \mathbf{\text{Very long loop of Henle}} \text{ (runs deep into medulla with vasa recta)} \end{aligned}

Step 3

Verbatim NCERT Reference

NCERT states verbatim: "In majority of nephrons, the loop of Henle is too short and extends only very little into the medulla. Such nephrons are called cortical nephrons. In some of the nephrons, the loop of Henle is very long and runs deep into the medulla. These nephrons are called juxta medullary nephrons." Reason R directly contradicts this and is unequivocally FALSE.

⭐

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:

Assertion is factually true, while Reason is blatantly false.

⚠️

Student Fallacy (Why candidates pick this trap): Accepting the inverted Henle loop lengths in Reason.

2 2

✗ Incorrect

Verdict & Scientific Reason:

Reason is false because juxtamedullary nephrons possess long loops of Henle.

⚠️

Student Fallacy (Why candidates pick this trap): Failing to catch the inverted description in Reason.

3 3

✗ Incorrect

Verdict & Scientific Reason:

Reason is factually false.

⚠️

Student Fallacy (Why candidates pick this trap): Assuming both statements are true without checking anatomical details.

4 4

✓ 100% Correct

Verdict & Scientific Reason:

Assertion A is correct, but Reason R is false due to complete reversal of Henle's loop length.

💡

Why this is airtight: None; rigorous anatomical precision.

⚠️

NTA Trap Alert: Cortical vs. Juxtamedullary Loop Length Inversion Trap

NTA frequently tests this exact inversion: juxtamedullary nephrons specialize in water conservation and creating the hyperosmotic medullary gradient, which REQUIRES a very long loop of Henle.

🛡️ How to avoid the -1 mark: Remember: Juxtamedullary = Deep in medulla = LONG loop of Henle. Cortical = Mostly in cortex = SHORT loop.

📖

Core NEET Syllabus Standard

NCERT Biology · Excretory Products and their Elimination Standard Benchmark

Core Scientific Principle Tested:

"Cortical nephrons have short loop of Henle extending very little into medulla; Juxtamedullary nephrons have very long loop of Henle running deep into medulla."

Syllabus Focus: Structure of Nephron

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2023 Zoology Question 160 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Henle Loop Inversion Alert: Juxtamedullary has LONG Loop!

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluation of Assertion A (Nephron Types)

Evaluation of Reason R (Henle's Loop Dimensions)

Verbatim NCERT Reference

360° Option Elimination Engine Key Feature

NTA Trap Alert: Cortical vs. Juxtamedullary Loop Length Inversion Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Excretory Products and their Elimination

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Juxtamedullary Nephrons: Structural Hallmarks and Medullary Penetration

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