Q.100 Botany ⭐ 360° Option Elimination Active

NEET 2025 Botany Question 100 Solution

Topic: Ecosystem · Official NTA Booklet Code 45

Question

Given below are two statements: Statement I: The primary source of energy in an ecosystem is solar energy. Statement II: The rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP). In the light of the above statements, choose the most appropriate answer from the options given below:

(1)Both statement I and statement II are correct
(2)Both statement I and statement II are incorrect
(3)Statement I is correct but statement II is incorrect
(4)Statement I is incorrect but statement II is correct

✓

Verified Against NTA Final Answer Key

Option (3) : Statement I is correct but statement II is incorrect

📚 Ecosystem Easy

📋 Given Parameters & Problem Setup

Statement I The primary source of energy in an ecosystem is solar energy.

Statement II The rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP).

⚡

The 30-Second Exam Hall Shortcut: ⚡ GPP vs NPP Definition Check

⏱️ Save ~25 seconds

Sun is the ultimate primary energy source for all ecosystems (Statement I is TRUE)! Rate of organic matter production during photosynthesis is GROSS Primary Productivity (GPP), NOT NPP! NPP = GPP - R! Statement II is FALSE ⟹ Statement I correct, statement II incorrect!

1 Check Statement I: Solar radiation is the ultimate driver of virtually all ecosystems on Earth (except deep-sea hydrothermal vents). Autotrophs fix solar energy into chemical energy. Statement I is TRUE.

2 Check Statement II: Total rate of production of organic matter during photosynthesis is defined as GROSS PRIMARY PRODUCTIVITY (GPP).

3 Net Primary Productivity (NPP) is the remaining biomass after accounting for respiratory losses (R): NPP = GPP - R.

4 Statement II incorrectly defines GPP as Net Primary Productivity (NPP). Hence Statement II is FALSE.

5 Conclusion: Statement I is correct but statement II is incorrect.

6 Select Option (3) in under 10 seconds!

🛡️

Why You Can 100% Trust This Shortcut: Ecosystem Productivity Dynamics (NCERT Biology · Ecosystem: Net Primary Productivity NPP = GPP - R).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluate Statement I (Source of Ecosystem Energy)

Examine energy flow in ecological food webs from NCERT Chapter 14:

\text{Solar Energy} \xrightarrow{\text{Photosynthesis}} \text{Primary Producers (Autotrophs)} \longrightarrow \text{Herbivores} \longrightarrow \text{Carnivores}

• Except for chemosynthetic deep-sea hydrothermal vent communities, the sun is the exclusive primary energy source for all biosphere ecosystems.
• Statement I is unequivocally TRUE.

Step 2

Evaluate Statement II (Gross vs. Net Primary Productivity)

Examine canonical definitions of ecological productivity:

\text{Gross Primary Productivity (GPP)} = \text{Total rate of organic matter synthesis during photosynthesis}

• A considerable amount of GPP is utilized by plants in cellular respiration (R).
• Net Primary Productivity (NPP) is the available biomass for consumption by heterotrophs:
• \text{NPP} = \text{GPP} - R.
• Statement II states that the total rate of production during photosynthesis is NPP, which conflates GPP with NPP.
• Statement II is completely FALSE.

Step 3

Select Matching Option

Statement I is correct and Statement II is incorrect, corresponding to Option (3).

\text{Statement I: True}, \quad \text{Statement II: False} \implies \text{Option (3)}

• Matches Option (3) with complete precision.

⭐

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. Statement II is false because it describes GPP, not NPP.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing gross and net primary productivity.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Statement I is true (sun is primary energy source).

⚠️

Student Fallacy (Why candidates pick this trap): Doubting solar energy as the primary source.

3 C

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. Sun is primary energy source (I); total photosynthetic rate is GPP, not NPP (II).

💡

Why this is airtight: None; rigorous grasp of ecosystem productivity.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Inverts truth values.

⚠️

Student Fallacy (Why candidates pick this trap): Multiple errors.

⚠️

NTA Trap Alert: Conflating GPP with NPP

Gross = TOTAL production during photosynthesis. Net = REMAINDER after plant respiration (NPP = GPP - R). The sentence in Statement II describes GROSS productivity verbatim!

🛡️ How to avoid the -1 mark: Remember: Total organic matter produced = GROSS (GPP); Leftover biomass = NET (NPP)!

📖

Core NEET Syllabus Standard

NEET Biology Core Syllabus · Ecosystem Standard Benchmark

Core Scientific Principle Tested:

"GPP is the rate of production of organic matter during photosynthesis; NPP = GPP - R."

Syllabus Focus: Energy Flow & Primary Productivity (GPP and NPP)

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Total made = GROSS (GPP)! Solar = Primary source! Statement I true, II false (Option 3)!

Ready to attempt under real exam pressure?

Test your speed and accuracy in the authentic 180-minute timed NTA simulator.

Launch NEET 2025 CBT Test →

← Previous (Q.99) All Botany Questions Grid Next (Q.101) →

Spotted a mistake in this solution? Report an error ([email protected])

⚖️ Legal & Fair Dealing Notice: Sourced from publicly released NEET 2025 question papers and NEET answer keys for private study, research, and non-commercial educational practice under Fair Dealing (Section 52(1)(a) of the Indian Copyright Act, 1957). Not affiliated with or endorsed by NTA or NMC.

NEET 2025 Botany Question 100 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ GPP vs NPP Definition Check

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluate Statement I (Source of Ecosystem Energy)

Evaluate Statement II (Gross vs. Net Primary Productivity)

Select Matching Option

360° Option Elimination Engine Key Feature

NTA Trap Alert: Conflating GPP with NPP

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

Ecological Energetics: Productivity Transfer Across Trophic Levels

Stages of Decomposition: Fragmentation, Leaching, Catabolism, Mineralization

Solve 4 NEET Questions a Day — One per Subject