Q.156 Zoology ⭐ 360° Option Elimination Active

NEET 2025 Zoology Question 156 Solution

Topic: Human Health and Disease · Official NTA Booklet Code 45

Question

After maturation, in primary lymphoid organs, the lymphocytes migrate for interaction with antigens to secondary lymphoid organ(s) / tissue(s) like: A. thymus B. bone marrow C. spleen D. lymph nodes E. Peyer's patches Choose the correct answer from the options given below:

✓

Verified Against NTA Final Answer Key

Option (4) : C, D, E only

📚 Human Health and Disease Easy

📋 Given Parameters & Problem Setup

List of Organs A. thymus, B. bone marrow, C. spleen, D. lymph nodes, E. Peyer's patches

Target Class Secondary lymphoid organ(s) / tissue(s) where mature lymphocytes interact with antigens

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The 30-Second Exam Hall Shortcut: ⚡ Lymphoid Organs Segregation Fingerprint

⏱️ Save ~25 seconds

Primary = Origin & Maturation (Bone marrow + Thymus = A & B)! Secondary = Antigen interaction & proliferation (Spleen + Lymph nodes + Peyer's patches = C, D, E)! C, D, E only!

1 Recall NCERT Section 8.2.5 (Lymphoid Organs):

2 - Primary lymphoid organs: Bone marrow and Thymus (where immature lymphocytes mature and differentiate into antigen-sensitive lymphocytes) -> A and B.

3 - Secondary lymphoid organs: Spleen, Lymph nodes, Tonsils, Peyer's patches of small intestine, and Appendix (where lymphocytes migrate, interact with antigens, and proliferate to become effector cells) -> C, D, E.

4 Target: Secondary lymphoid organs = C, D, E only (Option 4)!

5 Solved in under 10 seconds!

🛡️

Why You Can 100% Trust This Shortcut: Acquired Immunodeficiency Syndrome (AIDS) Pathology (NCERT Biology · Human Health and Disease: HIV attacks CD4+ T-helper lymphocytes).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Classification of the Human Lymphoid System

Lymphoid organs are categorized into primary and secondary lymphoid organs based on their anatomical and immunological roles:

• Primary Lymphoid Organs: Organs where immature lymphocytes originate, proliferate, and differentiate into antigen-sensitive mature lymphocytes. In humans, these are Bone marrow (B) and Thymus (A).
• After maturation, these immunocompetent T and B lymphocytes migrate via the bloodstream into secondary lymphoid organs.

Step 2

Secondary Lymphoid Organs and Tissues (C, D, E)

Sites of antigen capture, presentation, and clonal expansion:

• C. Spleen: A large bean-shaped organ containing lymphocytes and phagocytes; filters blood by trapping blood-borne microorganisms and acts as a reservoir of erythrocytes.
• D. Lymph nodes: Small solid structures located along the lymphatic system; trap antigens carried in lymph and tissue fluid, activating lymphocytes to elicit immune responses.
• E. Peyer's patches: Unencapsulated aggregates of mucosal lymphoid follicles located in the submucosa of the small intestine (ileum), representing Gut-Associated Lymphoid Tissue (GALT).
• All three (C, D, E) provide the microenvironment where lymphocytes interact with trapped antigens.

Step 3

Conclusion

Secondary lymphoid organs/tissues among the choices are C, D, and E only, corresponding to Option (4).

\text{Secondary Lymphoid} = \{C\text{ (Spleen)}, \; D\text{ (Lymph nodes)}, \; E\text{ (Peyer's patches)}\}

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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

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Erroneously includes bone marrow (B), which is a primary lymphoid organ.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing primary bone marrow with secondary organs.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Thymus (A) and bone marrow (B) are primary lymphoid organs.

⚠️

Student Fallacy (Why candidates pick this trap): Listing primary organs instead of secondary organs.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Contains both primary organs (A and B).

⚠️

Student Fallacy (Why candidates pick this trap): Failing to distinguish primary from secondary sites.

4 D

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. Accurately isolates the three secondary lymphoid tissues (spleen, lymph nodes, Peyer's patches).

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Why this is airtight: None; pristine immunological classification.

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NTA Trap Alert: Primary vs Secondary Site Functions

Primary = School / Training academy (Origin & Maturation: Bone marrow & Thymus). Secondary = Battlefield (Interaction with Antigens: Spleen, Lymph nodes, Peyer's patches, Tonsils).

🛡️ How to avoid the -1 mark: B and T cells "graduate" in Bone marrow/Thymus (Primary) and "fight" in Spleen/Nodes/Peyer's (Secondary).

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Core NEET Syllabus Standard

NEET Biology Core Syllabus · Human Health and Disease Standard Benchmark

Core Scientific Principle Tested:

"Bone marrow and thymus are primary lymphoid organs; spleen, lymph nodes, and Peyer's patches are secondary lymphoid organs."

Syllabus Focus: Immune System in the Body · Lymphoid Organs

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Primary = Born & Trained (B & T: Bone marrow, Thymus); Secondary = Soldiers Patrol (Spleen, Nodes, Peyer's)!

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NEET 2025 Zoology Question 156 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Lymphoid Organs Segregation Fingerprint

Step-by-Step Rigorous Workflow & Mathematical Proof

Classification of the Human Lymphoid System

Secondary Lymphoid Organs and Tissues (C, D, E)

Conclusion

360° Option Elimination Engine Key Feature

NTA Trap Alert: Primary vs Secondary Site Functions

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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