Q.132 Botany ⭐ 360° Option Elimination Active

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NEET 2023 Botany Question 132 Solution

Topic: Ecosystem · Official NTA Booklet Code G5

Question

In the equation GPP is Gross Primary Productivity NPP is Net Primary Productivity R here is.

(1)Reproductive allocation
(2)Photosynthetically active radiation
(3)Respiratory quotient
(4)Respiratory loss

✓

Verified Against NTA Final Answer Key

Option (4) : Respiratory loss

📚 Ecosystem Easy

📋 Given Parameters & Problem Setup

Equation GPP - R = NPP

GPP Gross Primary Productivity

NPP Net Primary Productivity

Unknown Parameter R

⚡

The 30-Second Exam Hall Shortcut: ⚡ Ecosystem Energy Budget: GPP - R = NPP

⏱️ Save ~20 seconds

A considerable amount of total biomass produced (GPP) is oxidized by plants to power their own metabolic activities. This expended portion is Respiratory loss (R), leaving Net Primary Productivity (NPP)!

1 GPP: Total rate of production of organic matter during photosynthesis.

2 R: Respiration losses by the autotrophic producers.

3 NPP = GPP - R: Available biomass for the consumption of heterotrophs.

4 Match Option (4) Respiratory loss.

🛡️

Why You Can 100% Trust This Shortcut: Canonical NCERT Ecosystem primary production energetic balance equation.

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Definition of Ecological Productivity Terms

Trophic energetics in ecosystems follow the fundamental conservation of biomass equation:

\text{\textbf{GPP}} - \mathbf{R} = \text{\textbf{NPP}} \implies \begin{cases} \text{GPP} & = \text{Gross Primary Productivity} \\[3pt] \mathbf{R} & = \mathbf{\text{Respiration loss / Respiratory loss}} \\[3pt] \text{NPP} & = \text{Net Primary Productivity} \end{cases}

Step 2

Verbatim NCERT Reference

NCERT states verbatim: "Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP)."

Step 3

Evaluation of Distractor Terms

Reproductive allocation describes the fraction of energy invested into gametes and floral structures. PAR is photosynthetically active radiation ( $400-700\text{ nm}$ ). Respiratory quotient ( $RQ$ ) is the ratio of volume of $CO_2$ evolved to $O_2$ consumed.

⭐

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

✗ Incorrect

Verdict & Scientific Reason:

Reproductive allocation is an evolutionary life-history parameter, not the respiratory deduction in primary productivity.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing reproductive energy partitioning with metabolic respiration.

2 2

✗ Incorrect

Verdict & Scientific Reason:

PAR represents incident radiant energy ( $400-700\text{ nm}$ ), not internal respiratory metabolic expenditure.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing solar input abbreviations with biomass losses.

3 3

✗ Incorrect

Verdict & Scientific Reason:

Respiratory quotient ( $RQ$ ) is the dimensionless ratio of $CO_2$ evolved to $O_2$ consumed during substrate oxidation.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing RQ (Respiratory Quotient) with R (Respiratory loss).

4 4

✓ 100% Correct

Verdict & Scientific Reason:

Verbatim NCERT: R in the equation GPP - R = NPP represents respiration losses.

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Why this is airtight: None; textbook verbatim.

⚠️

NTA Trap Alert: Respiratory Quotient vs. Respiratory Loss Trap

Both terms begin with "Respirat-" and relate to respiration. RQ is a dimensionless gas ratio ( $RQ = CO_2/O_2$ ), while R in productivity is biomass lost to respiration.

🛡️ How to avoid the -1 mark: In ecological productivity equations, R ALWAYS stands for Respiration Loss.

📖

Core NEET Syllabus Standard

NCERT Biology · Ecosystem Standard Benchmark

Core Scientific Principle Tested:

"Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP). GPP - R = NPP."

Syllabus Focus: Productivity

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2023 Botany Question 132 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Ecosystem Energy Budget: GPP - R = NPP

Step-by-Step Rigorous Workflow & Mathematical Proof

Definition of Ecological Productivity Terms

Verbatim NCERT Reference

Evaluation of Distractor Terms

360° Option Elimination Engine Key Feature

NTA Trap Alert: Respiratory Quotient vs. Respiratory Loss Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Ecosystem

Trophic Levels and Consumer Classification in Grazing Food Chains

Unidirectional Energy Flow & Lindeman's 10% Law

Solar Energy as Primary Energy Source & Gross vs. Net Primary Productivity

Productivity of an Ecosystem and Its Units

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