Q.146 Botany ⭐ 360° Option Elimination Active

NEET 2024 Botany Question 146 Solution

Topic: Plant Kingdom · Official NTA Booklet Code T1

Question

Read the following statements and choose the set of correct statements: In the members of Phaeophyceae, A. Asexual reproduction occurs usually by biflagellate zoospores. B. Sexual reproduction is by oogamous method only. C. Stored food is in the form of carbohydrates which is either mannitol or laminarin. D. The major pigments found are chlorophyll a, c and carotenoids and xanthophyll. E. Vegetative cells have a cellulosic wall, usually covered on the outside by gelatinous coating of algin. Choose the correct answer from the options given below:

✓

Verified Against NTA Final Answer Key

Option (1) : A, C, D and E only

📚 Plant Kingdom Medium

📋 Given Parameters & Problem Setup

Algal Class Phaeophyceae (Brown algae)

Statements A: Biflagellate zoospores; B: Sexual reproduction oogamous only (False); C: Stored food mannitol/laminarin; D: Chl a, c, carotenoids, xanthophylls; E: Cellulosic wall with algin

⚡

The 30-Second Exam Hall Shortcut: ⚡ Brown Algae Sexual Diversity Rule

⏱️ Save ~35 seconds

Statement B claims sexual reproduction is "by oogamous method only". NCERT explicitly states sexual reproduction may be isogamous, anisogamous OR oogamous! Eliminate B!

1 Check Statement B: "Sexual reproduction is by oogamous method only" -> FALSE! In Phaeophyceae, sexual reproduction can be isogamous, anisogamous, or oogamous.

2 Eliminate every option with B: Option 2 (A, B, C, E), Option 3 (A, B, C, D), Option 4 (B, C, D, E).

3 Only Option (1) A, C, D and E only remains!

4 Single-step elimination gives the correct answer!

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Plant Kingdom (Phaeophyceae - Brown Algae)

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluate Statement A (Asexual Reproduction)

Asexual reproduction in most brown algae is by biflagellate zoospores that are pear-shaped and have two unequal laterally attached flagella. Statement A is true.

Step 2

Evaluate Statement B (Sexual Reproduction Modes)

Sexual reproduction may be isogamous, anisogamous or oogamous. Union of gametes may take place in water or within the oogonium (oogamous species). Restricting it to "oogamous method only" is factually incorrect. Statement B is false.

Step 3

Evaluate Statements C, D, and E (Biochemical Features)

- Statement C: Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol. True. - Statement D: Brown algae possess chlorophyll a, c, carotenoids and xanthophylls (fucoxanthin). True. - Statement E: The vegetative cells have a cellulosic wall usually covered on the outside by a gelatinous coating of algin. True.

Step 4

Formulate Valid Combination

Statements A, C, D, and E are correct, corresponding to Option (1).

⭐

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)

✓ 100% Correct

Verdict & Scientific Reason:

Accurately selects all valid structural, biochemical, and reproductive characteristics while rejecting statement B.

💡

Why this is airtight: None.

2 (2)

✗ Incorrect

Verdict & Scientific Reason:

Incorrectly includes Statement B and omits diagnostic pigments (D).

⚠️

Student Fallacy (Why candidates pick this trap): Incorrectly includes Statement B and omits diagnostic pigments (D).

3 (3)

✗ Incorrect

Verdict & Scientific Reason:

Incorrectly includes Statement B and omits cell wall algin coating (E).

⚠️

Student Fallacy (Why candidates pick this trap): Incorrectly includes Statement B and omits cell wall algin coating (E).

4 (4)

✗ Incorrect

Verdict & Scientific Reason:

Incorrectly includes Statement B and omits biflagellate zoospores (A).

⚠️

Student Fallacy (Why candidates pick this trap): Incorrectly includes Statement B and omits biflagellate zoospores (A).

⚠️

NTA Trap Alert: Phaeophyceae vs Rhodophyceae Sexual Reproduction

Confusing Rhodophyceae (which is strictly oogamous with non-motile gametes) with Phaeophyceae.

🛡️ How to avoid the -1 mark: Rhodophyceae is strictly oogamous; Phaeophyceae exhibits isogamous, anisogamous, and oogamous sexual reproduction.

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Core NEET Syllabus Standard

Biology Core Botany · Plant Kingdom Standard Benchmark

Core Scientific Principle Tested:

"Phaeophyceae possess chlorophyll a, c, carotenoids and xanthophylls. Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol. The vegetative cells have a cellulosic wall usually covered on the outside by a gelatinous coating of algin... Asexual reproduction is by pear-shaped biflagellate zoospores... Sexual reproduction may be isogamous, anisogamous or oogamous."

Syllabus Focus: Phaeophyceae (Brown Algae): Reproduction, Storage, Pigments, and Cell Wall

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2024 Botany Question 146 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Brown Algae Sexual Diversity Rule

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluate Statement A (Asexual Reproduction)

Evaluate Statement B (Sexual Reproduction Modes)

Evaluate Statements C, D, and E (Biochemical Features)

Formulate Valid Combination

360° Option Elimination Engine Key Feature

NTA Trap Alert: Phaeophyceae vs Rhodophyceae Sexual Reproduction

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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