Q.109 Botany ⭐ 360° Option Elimination Active
NEET 2021 Botany Question 109 Solution
Topic: Organisms and Populations · Official NTA Booklet Code M1
Question
Amensalism can be represented as:
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Verified Against NTA Final Answer Key
Option (1) : Species A ( - ) ; Species B ( 0 )
📚 Organisms and Populations Easy
📋 Given Parameters & Problem Setup
Interaction Type Amensalism
Symbolism (+) Beneficial, (-) Detrimental, (0) Neutral
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⏱️ Save ~15 seconds The 30-Second Exam Hall Shortcut: ⚡ Amensalism = "Harm and Neutral" = (- , 0)
In amensalism, one species is harmed (-) while the other species is neither harmed nor benefited (0). For example, Penicillium secretes penicillin inhibiting bacteria without gaining or losing. Match Option (1)!
1 Mutualism: (+, +).
2 Competition: (-, -).
3 Predation & Parasitism: (+, -).
4 Commensalism: (+, 0).
5 Amensalism: (-, 0).
6 Match Option (1).
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Why You Can 100% Trust This Shortcut: Canonical NCERT Ecology taxonomy on Population Interactions.
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Step-by-Step Rigorous Workflow & Mathematical Proof
Step 1
Definition of Amensalism
Amensalism is an interspecific ecological interaction wherein one species suffers negative effects (inhibition, injury, or death) while the second species remains completely unaffected:
Step 2
Biological Examples
Classic textbook manifestations include: - Antibiosis: *Penicillium notatum* secretes the antibiotic penicillin, destroying surrounding bacterial colonies while *Penicillium* itself experiences no nutritional or reproductive change (). - Allelopathy: Roots of Black Walnut (*Juglans nigra*) release juglone, inhibiting germination of nearby herbaceous seedlings without direct benefit to the tree.
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4-Option Deep Scan
360° Option Elimination Engine Key Feature
Diagnose every choice: Know exactly why the right option works and why distractors fail.
1 1
✓ 100% Correct Verdict & Scientific Reason:
Accurate representation of amensalism: one partner is inhibited/harmed (-) while the other remains neutral (0).
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Why this is airtight: None. Direct textbook match.
2 2
✗ Incorrect Verdict & Scientific Reason:
Represents mutualism, where both interacting species derive positive fitness benefits.
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Student Fallacy (Why candidates pick this trap): Confusing amensalism with mutualism.
3 3
✗ Incorrect Verdict & Scientific Reason:
Represents interspecific competition, where both interacting species suffer negative fitness impacts.
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Student Fallacy (Why candidates pick this trap): Confusing amensalism with competition.
4 4
✗ Incorrect Verdict & Scientific Reason:
Represents commensalism, where one species benefits (+) and the other is unaffected (0).
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Student Fallacy (Why candidates pick this trap): Swapping the negative (-) sign for harm with the positive (+) sign for benefit, conflating amensalism with commensalism.
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NTA Trap Alert: Commensalism (+, 0) vs Amensalism (-, 0) Sign Inversion
Both interactions feature one neutral partner (0), making hasty candidates confuse (+, 0) for commensalism with (-, 0) for amensalism.
🛡️ How to avoid the -1 mark: Remember: "Co" = cooperate/benefit (+, 0) for Commensalism; "A" = Adversity/harm (-, 0) for Amensalism.
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Core NEET Syllabus Standard
NEET / NCERT Biology · Organisms and Populations Standard Benchmark
Core Scientific Principle Tested:
"In amensalism, one species is harmed whereas the other is unaffected."
Syllabus Focus: Population Interactions
✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗
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