Q.111 Botany ⭐ 360° Option Elimination Active

NEET 2025 Botany Question 111 Solution

Topic: Plant Kingdom · Official NTA Booklet Code 45

Question

Given below are the stages in the life cycle of pteridophytes. Arrange the following stages in the correct sequence. A. Prothallus stage B. Meiosis in spore mother cells C. Fertilisation D. Formation of archegonia and antheridia in gametophyte. E. Transfer of antherozoids to the archegonia in presence of water. Choose the correct answer from the options given below:

(1)B,A, D, E, C
(2)B, A, E, C, D
(3)D,E,C, A,B
(4)E,D,C,B,A

✓

Verified Against NTA Final Answer Key

Option (1) : B, A, D, E, C

📚 Plant Kingdom Medium

📋 Given Parameters & Problem Setup

Stage A Prothallus stage

Stage B Meiosis in spore mother cells

Stage C Fertilisation

Stage D Formation of archegonia and antheridia in gametophyte

Stage E Transfer of antherozoids to the archegonia in presence of water

⚡

The 30-Second Exam Hall Shortcut: ⚡ Pteridophyte Life Cycle Sequence Fingerprint

⏱️ Save ~35 seconds

Meiosis in SMC (B) -> Haploid Spores germinate to Prothallus (A) -> Sex organs form (D) -> Water transfers antherozoids (E) -> Syngamy / Fertilisation (C)! Sequence: B -> A -> D -> E -> C!

1 Establish the chronological order of sexual reproduction in ferns/pteridophytes:

2 Diploid sporophyte bears sporangia where Spore Mother Cells undergo Meiosis (B) to form haploid spores.

3 Spores germinate in cool, damp places to form the multicellular free-living Prothallus (A).

4 Prothallus (gametophyte) develops sex organs: Antheridia and Archegonia (D).

5 Water is essential for Transfer of flagellated antherozoids to the mouth of the archegonium (E).

6 Fusion of gametes: Fertilisation (C) produces the diploid zygote which grows into a new sporophyte.

7 Correct order: B -> A -> D -> E -> C (Option 1)!

8 Select Option (1) confidently!

🛡️

Why You Can 100% Trust This Shortcut: Pteridophyte Classification & Spore Dynamics (NCERT Biology · Plant Kingdom: Heterospory in Selaginella and Salvinia).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Sporophytic Phase and Spore Genesis

In pteridophytes, the main plant body is a diploid sporophyte differentiated into true root, stem, and leaves:

• Sporophylls bear sporangia containing diploid spore mother cells (SMCs).
• SMCs undergo reduction division (Meiosis in spore mother cells - Stage B) to produce haploid spores.

Step 2

Gametophytic Phase (Prothallus) and Sex Organ Development

Development of the independent, photosynthetic gametophytic generation:

• Haploid spores germinate to produce inconspicuous, small, multicellular, free-living, mostly photosynthetic thalloid gametophytes called the Prothallus stage (Stage A).
• The prothallus bears male and female sex organs: antheridia and archegonia (Stage D).

Step 3

Water-Mediated Gamete Transfer and Syngamy

Completion of the sexual cycle:

• Water is required for the transfer of flagellated male gametes (antherozoids) released from antheridia to the archegonium (Stage E).
• Fusion of an antherozoid with the egg present in the archegonium results in Fertilisation (Stage C).
• The resulting zygote produces a multicellular, well-differentiated sporophyte, restarting the cycle.

Step 4

Sequence Synthesis

Ordering the stages: B (Meiosis) -> A (Prothallus) -> D (Archegonia & Antheridia formation) -> E (Transfer of antherozoids in water) -> C (Fertilisation).

\text{Cycle: } B \rightarrow A \rightarrow D \rightarrow E \rightarrow C

⭐

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:

100% correct. Precisely traces the alternating sporophyte-to-gametophyte-to-syngamy developmental continuum.

💡

Why this is airtight: None; clear chronological grasp.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Places transfer of antherozoids (E) and fertilisation (C) before sex organs are formed (D), which is biologically impossible.

⚠️

Student Fallacy (Why candidates pick this trap): Putting gamete release before organ formation.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Starts with sex organs (D) before the prothallus (A) has even formed.

⚠️

Student Fallacy (Why candidates pick this trap): Reversing the sequence.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Disordered chronology starting with antherozoid transfer.

⚠️

Student Fallacy (Why candidates pick this trap): Arbitrary ordering.

⚠️

NTA Trap Alert: Starting Point of the Alternation Cycle

Look at the provided options: all realistic candidates start with B (Meiosis in SMCs) or D. Since the prothallus is formed from spores produced by meiosis, B must precede A, and D must occur on A!

🛡️ How to avoid the -1 mark: Trace from Spore production (Meiosis, B) -> Thallus (A) -> Organs (D) -> Swimming (E) -> Fusion (C).

📖

Core NEET Syllabus Standard

NEET Biology Core Syllabus · Plant Kingdom Standard Benchmark

Core Scientific Principle Tested:

"Meiosis in SMCs produces spores which germinate into a prothallus bearing antheridia/archegonia; antherozoids swim in water to effect fertilisation."

Syllabus Focus: Pteridophytes · Alternation of Generations

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

BAD EC: B (Meiosis) -> A (Prothallus) -> D (Duo Organs) -> E (Enter water) -> C (Conception/Fertilisation)!

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NEET 2025 Botany Question 111 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Pteridophyte Life Cycle Sequence Fingerprint

Step-by-Step Rigorous Workflow & Mathematical Proof

Sporophytic Phase and Spore Genesis

Gametophytic Phase (Prothallus) and Sex Organ Development

Water-Mediated Gamete Transfer and Syngamy

Sequence Synthesis

360° Option Elimination Engine Key Feature

NTA Trap Alert: Starting Point of the Alternation Cycle

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Plant Kingdom

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