Q.155 Zoology ⭐ 360° Option Elimination Active

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NEET 2025 Zoology Question 155 Solution

Topic: Morphology of Flowering Plants · Official NTA Booklet Code 45

Question

Which of the following is an example of a zygomorphic flower?

(1)Petunia
(2)Datura
(3)Pea
(4)Chilli

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Verified Against NTA Final Answer Key

Option (3) : Pea

📚 Morphology of Flowering Plants Easy

📋 Given Parameters & Problem Setup

Symmetry Type Zygomorphic (bilateral floral symmetry)

Target Example Representative plant species

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The 30-Second Exam Hall Shortcut: ⚡ Floral Symmetry Fingerprint

⏱️ Save ~15 seconds

Actinomorphic (radial) = Mustard, Datura, Chilli! Zygomorphic (bilateral) = PEA, Gulmohur, Bean, Cassia! Pea is Zygomorphic!

1 Recall floral symmetry definitions and examples from NCERT Section 5.3:

2 - Actinomorphic (radial symmetry): Can be divided into two equal radial halves in any radial plane passing through the centre. Examples: Mustard, Datura, Chilli, Petunia (Solanaceae).

3 - Zygomorphic (bilateral symmetry): Can be divided into two similar halves only in ONE particular vertical plane. Examples: Pea, Gulmohur, Bean, Cassia.

4 - Asymmetric (irregular): Canna.

5 Direct match for zygomorphic: Pea!

6 Select Option (3) Pea!

🛡️

Why You Can 100% Trust This Shortcut: Stem Modifications & Tendril/Thorn Homology (NCERT Biology · Morphology of Flowering Plants: Axillary bud origin).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Definition of Zygomorphic Symmetry

Floral symmetry is a primary taxonomic character in angiosperm classification:

• A flower is zygomorphic (bilaterally symmetrical) when it can be divided into two equal and similar halves along only one single vertical median longitudinal plane.
• In floral diagrams and formulas, zygomorphic symmetry is denoted by the percentage sign ( $\%$ ).

Step 2

Evaluation of the Given Candidates

Classifying the provided options based on NCERT examples:

• 1. Petunia: Belongs to family Solanaceae; flowers are actinomorphic (radial symmetry, $\oplus$ ).
• 2. Datura: Belongs to family Solanaceae; flowers are actinomorphic (radial symmetry, $\oplus$ ).
• 3. Pea (*Pisum sativum*): Belongs to family Fabaceae; flowers have vexillary (papilionaceous) aestivation with standard, wings, and keel, making them distinctly zygomorphic ( $\%, C_{1+2+(2)}$ ).
• 4. Chilli (*Capsicum annuum*): Belongs to family Solanaceae; flowers are actinomorphic (radial symmetry, $\oplus$ ).

Step 3

Conclusion

Among the choices, Pea is the definitive example of a zygomorphic flower.

\text{Zygomorphic Flower} = \text{Pea (Pisum sativum)}

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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. Petunia has actinomorphic flowers characteristic of family Solanaceae.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing Solanaceae symmetry with Fabaceae symmetry.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Datura is an NCERT textbook example of an actinomorphic flower.

⚠️

Student Fallacy (Why candidates pick this trap): Ignoring NCERT explicit listing of Datura as actinomorphic.

3 C

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. Pea possesses classic papilionaceous zygomorphic flowers dividable along only one vertical plane.

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Why this is airtight: None; textbook mastery.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Chilli is explicitly cited by NCERT as an actinomorphic flower.

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Student Fallacy (Why candidates pick this trap): Confusing chilli with pea.

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NTA Trap Alert: Fabaceae vs Solanaceae Symmetry

Remember the family-level symmetries: All Fabaceae (Pea, Bean, Gram, Moong, Arhar) are ZYGOMORPHIC (%). All Solanaceae (Potato, Tomato, Brinjal, Chilli, Datura, Petunia) are ACTINOMORPHIC (⊕)!

🛡️ How to avoid the -1 mark: Solanaceae = Actinomorphic; Fabaceae = Zygomorphic.

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Core NEET Syllabus Standard

NEET Biology Core Syllabus · Morphology of Flowering Plants Standard Benchmark

Core Scientific Principle Tested:

"Flowers of pea, gulmohur, bean, and cassia are zygomorphic (bilaterally symmetrical)."

Syllabus Focus: The Flower · Floral Symmetry

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Z-PGBC: Zygomorphic = Pea, Gulmohur, Bean, Cassia!

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NEET 2025 Zoology Question 155 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Floral Symmetry Fingerprint

Step-by-Step Rigorous Workflow & Mathematical Proof

Definition of Zygomorphic Symmetry

Evaluation of the Given Candidates

Conclusion

360° Option Elimination Engine Key Feature

NTA Trap Alert: Fabaceae vs Solanaceae Symmetry

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Morphology of Flowering Plants

Definition and Patterns of Phyllotaxy (Leaf Arrangement)

Diagnostic Characters of Family Solanaceae (Potato Family)

Types of Placentation in Angiospermic Ovaries

Types of Flowers Based on Ovary Position: Perigynous Flowers

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