Q.156 Zoology ⭐ 360° Option Elimination Active

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NEET 2026 Zoology Question 156 Solution

Topic: Sexual Reproduction in Flowering Plants · Official NTA Booklet Code 50

Question

If the diploid chromosome number of typical angiosperm is 36, what would be the chromosome number in its endosperm?

(1)18
(2)36
(3)54
(4)72

✓

Verified Against NTA Final Answer Key

Option (3) : 54

📚 Sexual Reproduction in Flowering Plants Easy

📋 Given Parameters & Problem Setup

Plant Type Angiosperm

Diploid Number (2n) 36

Target Structure Endosperm Chromosome Number

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The 30-Second Exam Hall Shortcut: ⚡ 3-Halves Ploidy Formula

⏱️ Save ~30 seconds

Endosperm = 3n = (3/2) × 2n = 1.5 × 36 = 54!

1 Recall angiosperm ploidy rules: Vegetative/sporophytic body is diploid (2n = 36).

2 Find haploid genome number: n = 36 / 2 = 18.

3 In angiosperms, endosperm is formed by triple fusion (1 male gamete n + 2 polar nuclei 2n = 3n).

4 Calculate: Endosperm = 3n = 3 × 18 = 54.

5 Match Option (3) = 54 instantly.

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Sexual Reproduction in Flowering Plants (Double Fertilization: Syngamy produces zygote, triple fusion produces PEN).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Determine Haploid Number (n)

Given that the diploid number of chromosomes (2n) of the angiospermic plant is 36, the haploid number (n) present in gametes is half of this value.

2n = 36 \implies n = \frac{36}{2} = 18

• Haploid number n = 18 applies to male gametes, egg cell, synergids, and antipodals.

Step 2

Triple Fusion and Endosperm Ploidy

In angiosperms, double fertilization involves triple fusion where one haploid male gamete (n) fuses with two haploid polar nuclei (or one secondary diploid nucleus 2n) to produce the triploid primary endosperm nucleus (PEN).

\text{PEN Ploidy} = n + n + n = 3n = 3 \times 18 = 54

• In gymnosperms, endosperm is haploid (n = 18); in angiosperms, it is triploid (3n = 54).

⭐

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. 18 is the haploid number (n), characteristic of gametes, synergids, and antipodals, or gymnosperm endosperm.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing angiosperm endosperm (3n) with haploid gametes or gymnosperm endosperm (n).

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. 36 is the diploid number (2n), characteristic of root, stem, leaf, integuments, and zygote.

⚠️

Student Fallacy (Why candidates pick this trap): Assuming endosperm has regular somatic diploid ploidy (2n).

3 C

✓ 100% Correct

Verdict & Scientific Reason:

100% mathematically and biologically correct. Angiosperm endosperm is triploid: 3n = 3 × 18 = 54.

💡

Why this is airtight: None; straightforward calculation.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. 72 would represent tetraploid (4n), which does not correspond to standard angiosperm endosperm.

⚠️

Student Fallacy (Why candidates pick this trap): Arbitrary multiplication by 4.

⚠️

NTA Trap Alert: Gymnosperm vs. Angiosperm Endosperm Ploidy Trap

In gymnosperms, endosperm is formed before fertilization and is haploid (n). In angiosperms, it is formed after double fertilization (triple fusion) and is triploid (3n).

🛡️ How to avoid the -1 mark: Always check if the question specifies "angiosperm" -> Endosperm is ALWAYS 3n.

📖

Core NEET Syllabus Standard

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

Core Scientific Principle Tested:

"Triple fusion results in a triploid (3n) primary endosperm nucleus."

Syllabus Focus: Double Fertilization & Endosperm

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Triple Fusion = 3 × n = 3 × 18 = 54!

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NEET 2026 Zoology Question 156 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ 3-Halves Ploidy Formula

Step-by-Step Rigorous Workflow & Mathematical Proof

Determine Haploid Number (n)

Triple Fusion and Endosperm Ploidy

360° Option Elimination Engine Key Feature

NTA Trap Alert: Gymnosperm vs. Angiosperm Endosperm Ploidy Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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