Q.61 Zoology ⭐ 360° Option Elimination Active

NEET 2020 Zoology Question 61 Solution

Topic: Principles of Inheritance and Variation · Official NTA Booklet Code E1

Question

How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits?

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Verified Against NTA Final Answer Key

Option (3) : 14

📚 Principles of Inheritance and Variation Easy

📋 Given Parameters & Problem Setup

Experimental Model Pisum sativum (Garden Pea)

Experimenter Gregor Johann Mendel

Question Objective Count of true-breeding varieties selected as pairs with contrasting traits

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The 30-Second Exam Hall Shortcut: ⚡ "7 Characters = 14 True-Breeding Varieties (7 Pairs)!"

⏱️ 20 seconds

Mendel selected 7 characters, each having 2 contrasting traits. Thus, he selected 14 true-breeding pea plant varieties as 7 pairs! The question asks "How many true breeding pea plant varieties did Mendel select" -> 14! Mark Option (3) in 5 seconds.

1 Mendel studied 7 characters in garden pea.

2 Each character had 2 contrasting traits (e.g. tall vs dwarf, yellow vs green seeds).

3 Total number of true-breeding varieties = 7 × 2 = 14 varieties.

4 Select Option (3) 14.

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Why You Can 100% Trust This Shortcut: NCERT Biology · Principles of Inheritance and Variation (Mendel's Laws of Inheritance)

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Examine NCERT Statement on Mendel's Varieties

NCERT states verbatim: "Mendel selected 14 true-breeding pea plant varieties, as pairs which were similar except for one character with contrasting traits."

Step 2

Understand the 7 Characters and 14 Traits

The 7 pairs of contrasting traits included: 1. Stem height (Tall / Dwarf) 2. Flower colour (Violet / White) 3. Flower position (Axial / Terminal) 4. Pod shape (Inflated / Constricted) 5. Pod colour (Green / Yellow) 6. Seed shape (Round / Wrinkled) 7. Seed colour (Yellow / Green).

Step 3

Distinguish Between Characters and Varieties

Number of characters = 7. Number of pairs of contrasting traits = 7. Total number of true-breeding plant varieties = 14.

Step 4

Conclude Correct Option

The question specifically asks for the number of true-breeding varieties, which is 14.

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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; 4 is not the number of varieties selected.

⚠️

Student Fallacy (Why candidates pick this trap): Random guess.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect; 2 is the number of contrasting traits per character, not the total number of varieties.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing traits per character with total varieties.

3 C

✓ 100% Correct

Verdict & Scientific Reason:

Factually exact; Mendel selected 14 true-breeding pea plant varieties (7 pairs).

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Why this is airtight: None; direct NCERT quotation.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect; 8 is irrelevant to Mendel's variety count.

⚠️

Student Fallacy (Why candidates pick this trap): Guessing.

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NTA Trap Alert: 7 Characters vs 14 Varieties

If the question asks for CHARACTERS = 7. If it asks for VARIETIES (or traits) = 14.

🛡️ How to avoid the -1 mark: Read the noun: "How many varieties" = 14! "How many characters" = 7!

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Core NEET Syllabus Standard

Zoology · Principles of Inheritance and Variation Standard Benchmark

Core Scientific Principle Tested:

Syllabus Focus: Mendel's Selection of True-Breeding Pea Plant Varieties (14 Varieties / 7 Pairs)

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2020 Zoology Question 61 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ "7 Characters = 14 True-Breeding Varieties (7 Pairs)!"

Step-by-Step Rigorous Workflow & Mathematical Proof

Examine NCERT Statement on Mendel's Varieties

Understand the 7 Characters and 14 Traits

Distinguish Between Characters and Varieties

Conclude Correct Option

360° Option Elimination Engine Key Feature

NTA Trap Alert: 7 Characters vs 14 Varieties

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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