Q.178 Zoology ⭐ 360° Option Elimination Active

NEET 2026 Zoology Question 178 Solution

Topic: Ecosystem · Official NTA Booklet Code 50

Question

Which of the following statements are correct? (a) Energy flow from producers to consumers is unidirectional (b) Energy pyramid can never be inverted (c) Transfer of energy follows the 1% law Choose the correct answer from the options given below:

(1)(a), (b) and (c)
(2)(a) and (b) only
(3)(a) and (c) only
(4)(b) and (c) only

✓

Verified Against NTA Final Answer Key

Option (2) : (a) and (b) only

📚 Ecosystem Easy

📋 Given Parameters & Problem Setup

Ecosystem Process Energy Flow and Ecological Pyramids

Given Statements (a) Energy flow is unidirectional; (b) Pyramid of energy is always upright; (c) Only about 1% of energy is transferred between trophic levels

⚡

The 30-Second Exam Hall Shortcut: ⚡ Lindeman’s 10% Law Filter

⏱️ Save ~40 seconds

Energy Flow = Unidirectional (a); Pyramid of Energy = ALWAYS Upright (b); Transfer = 10%, NOT 1% (c is FALSE)!

1 Check Statement (a): Energy flow in an ecosystem is unidirectional (Sun -> Producers -> Consumers) -> TRUE.

2 Check Statement (b): Pyramid of energy is always upright and can never be inverted -> TRUE (NCERT verbatim).

3 Check Statement (c): "Only about 1% of energy is transferred..." -> FALSE! (Lindeman’s law states ~10% of energy is transferred; 1% is the PAR captured by plants from incident solar radiation).

4 Therefore, only (a) and (b) are correct.

5 Select Option (2): (a) and (b) only in under 10 seconds!

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Ecosystem (Carbon and Phosphorus Nutrient Cycles: Reservoir pool differences).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Unidirectional Flow of Energy

Energy flows unidirectionally from the sun to producers and then to consumers, obeying the first and second laws of thermodynamics. Energy once dissipated as metabolic heat can never be recycled back to previous trophic levels. Thus, Statement (a) is correct.

\text{Solar Energy} \xrightarrow{\text{Unidirectional}} \text{Producers} \rightarrow \text{Herbivores} \rightarrow \text{Carnivores} \xrightarrow{\text{Heat Dissipation}} \text{Environment}

• Pyramid of energy is always upright because energy is lost as heat at each step.

Step 2

Pyramid of Energy and Lindeman's 10% Law

Pyramid of energy is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. According to Lindeman’s 10 percent law, only 10% of the energy is transferred to each trophic level from the lower trophic level, not 1%. Thus, Statement (b) is true, but Statement (c) is false.

\text{Energy at Level } (n+1) = 0.10 \times \text{Energy at Level } (n) \quad (\mathbf{10\% \text{ Law}}, \neq 1\%)

• Plants capture only 2-10% of PAR (which is ~1% of incident total solar radiation), but trophic level transfer efficiency is 10%.

⭐

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 because statement (c) is false (10% law, not 1%).

⚠️

Student Fallacy (Why candidates pick this trap): Confusing 1% PAR capture from total sunlight with trophic level transfer efficiency.

2 B

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. Statements (a) and (b) are canonical ecological laws, while statement (c) misstates Lindeman’s 10% law.

💡

Why this is airtight: None; clear differentiation between 10% transfer and 1% solar capture.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Statement (a) is true, and statement (c) is false.

⚠️

Student Fallacy (Why candidates pick this trap): Failing to recognize unidirectional energy flow.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Statement (b) is true and statement (c) is false.

⚠️

Student Fallacy (Why candidates pick this trap): Omitting the universal upright nature of energy pyramids.

⚠️

NTA Trap Alert: 1% Solar Capture vs. 10% Trophic Transfer Trap

Students often mix up the numbers: Plants capture ~1-2% of total incident solar radiation (2-10% of PAR), but between trophic levels, energy transfer follows the 10% LAW (Lindeman).

🛡️ How to avoid the -1 mark: Trophic transfer = 10% Law; Sunlight capture = 1-2% of incident radiation.

📖

Core NEET Syllabus Standard

NEET Biology Core Syllabus · Ecosystem Standard Benchmark

Core Scientific Principle Tested:

"Energy flow is unidirectional, the pyramid of energy is always upright, and trophic transfer follows the 10% law."

Syllabus Focus: Energy Flow & Ecological Pyramids

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Energy flows One-Way, Pyramids Stand Upright, Lindeman gave us TEN Percent!

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NEET 2026 Zoology Question 178 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Lindeman’s 10% Law Filter

Step-by-Step Rigorous Workflow & Mathematical Proof

Unidirectional Flow of Energy

Pyramid of Energy and Lindeman's 10% Law

360° Option Elimination Engine Key Feature

NTA Trap Alert: 1% Solar Capture vs. 10% Trophic Transfer Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Ecosystem

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

Productivity of an Ecosystem and Its Units

Thermodynamics of Ecosystems and Unidirectional Energy Flow

Ecological Energetics: Productivity Transfer Across Trophic Levels

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