Q.127 Botany ⭐ 360° Option Elimination Active

NEET 2025 Botany Question 127 Solution

Topic: Sexual Reproduction in Flowering Plants · Official NTA Booklet Code 45

Question

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): A typical unfertilised, angiosperm embryo sac at maturity is 8 nucleate and 7-celled. Reason (R): The egg apparatus has 2 polar nuclei. In the light of the above statements, choose the correct answer from the options given below:

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

✓

Verified Against NTA Final Answer Key

Option (3) : A is true but R is false

📚 Sexual Reproduction in Flowering Plants Medium

📋 Given Parameters & Problem Setup

Assertion (A) A typical unfertilised, angiosperm embryo sac at maturity is 8 nucleate and 7-celled.

Reason (R) The egg apparatus has 2 polar nuclei.

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The 30-Second Exam Hall Shortcut: ⚡ Embryo Sac Anatomy Fingerprint

⏱️ Save ~25 seconds

Assertion is TRUE (7-celled, 8-nucleate Polygonum type)! Reason is FALSE because polar nuclei are in the CENTRAL CELL, NOT in the egg apparatus (egg apparatus has 1 egg + 2 synergids)! A is true, R is false!

1 Analyze Assertion (A):

2 - "A typical unfertilised angiosperm embryo sac at maturity is 8-nucleate and 7-celled." -> Standard Polygonum type embryo sac! Assertion (A) is TRUE.

3 Analyze Reason (R):

4 - "The egg apparatus has 2 polar nuclei." -> Completely FALSE! The egg apparatus consists of THREE cells: two synergids and one egg cell. The 2 polar nuclei reside in the large CENTRAL CELL!

5 Conclusion: A is true but R is false.

6 Select Option (3)!

🛡️

Why You Can 100% Trust This Shortcut: Pollen Pistil Interaction & Double Fertilization (NCERT Biology · Sexual Reproduction in Flowering Plants: Syngamy and triple fusion).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Analysis of Assertion (A)

Development of the female gametophyte (embryo sac) in typical angiosperms (Polygonum type):

• A single functional megaspore undergoes three successive free nuclear mitotic divisions to produce an 8-nucleate stage.
• Cytokinesis subsequently partitions 6 of the nuclei into separate cells, while 2 nuclei remain in the central compartment.
• The mature embryo sac comprises 7 cells: 3 antipodal cells at chalazal end, 1 three-celled egg apparatus at micropylar end, and 1 large central cell containing 2 polar nuclei.
• Hence, Assertion (A) is completely TRUE.

Step 2

Analysis of Reason (R)

Composition of the Egg Apparatus vs Central Cell:

• The egg apparatus is located strictly at the micropylar end and consists of THREE cells: two synergids (with filiform apparatus) and one egg cell (female gamete).
• The 2 polar nuclei are located in the large central cell, situated below the egg apparatus.
• Therefore, asserting that "The egg apparatus has 2 polar nuclei" is anatomically and biologically FALSE.

Step 3

Conclusion

Assertion (A) is true, but Reason (R) is false. This leads directly to Option (3).

\text{Assertion: True}, \quad \text{Reason: False} \implies \text{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 A

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Reason R is blatantly false because polar nuclei belong to the central cell, not the egg apparatus.

⚠️

Student Fallacy (Why candidates pick this trap): Believing polar nuclei are part of the egg apparatus.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Reason R is false, so it cannot be true.

⚠️

Student Fallacy (Why candidates pick this trap): Failing to spot the anatomical error in R.

3 C

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. Accurately verifies that A is true while debunking the incorrect anatomical claim in R.

💡

Why this is airtight: None; precise botanical morphology.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Inverts the veracity of both statements.

⚠️

Student Fallacy (Why candidates pick this trap): Doubting the 7-celled, 8-nucleate nature of angiosperm embryo sac.

⚠️

NTA Trap Alert: Components of Egg Apparatus vs Central Cell

Egg Apparatus = 2 Synergids + 1 Egg Cell (Total 3 cells, 3 nuclei). Central Cell = 1 Cell containing 2 Polar Nuclei. Antipodals = 3 Cells, 3 nuclei. Total = 7 cells, 8 nuclei!

🛡️ How to avoid the -1 mark: Never attribute polar nuclei to the egg apparatus; they belong exclusively to the central cell.

📖

Core NEET Syllabus Standard

NEET Biology Core Syllabus · Sexual Reproduction in Flowering Plants Standard Benchmark

Core Scientific Principle Tested:

"An angiosperm embryo sac is 7-celled and 8-nucleate; the egg apparatus consists of 2 synergids and 1 egg cell, while polar nuclei reside in the central cell."

Syllabus Focus: Megasporogenesis & Female Gametophyte

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Egg Apparatus = 2 Synergids + 1 Egg (NO Polar Nuclei in the apparatus)!

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NEET 2025 Botany Question 127 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Embryo Sac Anatomy Fingerprint

Step-by-Step Rigorous Workflow & Mathematical Proof

Analysis of Assertion (A)

Analysis of Reason (R)

Conclusion

360° Option Elimination Engine Key Feature

NTA Trap Alert: Components of Egg Apparatus vs Central Cell

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Sexual Reproduction in Flowering Plants

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