1. 100x/3x(kcal m⁻²) yr⁻¹ 2. x/10(kcal m⁻²) yr⁻¹ 3. x (kcal m⁻²) yr⁻¹ 4. 10x (kcal m⁻²) yr⁻¹

Answer: 4. 10x (kcal m⁻²) yr⁻¹ Key idea: the energy a trophic level can pass on is its net productivity; about 10 percent of it is stored by the next level (10 percent law). Producers: NPP =100x . This is the energy available to the second level, so the second level's GPP ≈100x (intake). Second level keeps about 10 percent: NPP ≈10x . That 10x is what is passed to the third level, so the GPP of the third level =10x . The answer is option 4, 10x , matching the official key. Honestly, the wording of 'GPP of a consumer' is loose, and counting differently gives x .

Topic: Energy flow and ecological pyramids· Ecology and Environment

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is100x (kcal m^-2) yr^-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

1. \(\frac{100x}{3x}(kcal\,m^{-2})\,yr^{-1}\)

2. \(\frac{x}{10}(kcal\,m^{-2})\,yr^{-1}\)

3. \(x\,(kcal\,m^{-2})\,yr^{-1}\)

4. \(10x\,(kcal\,m^{-2})\,yr^{-1}\)

Doubtly Asked 30 Oct 2026 NEET UG 2024 Practice test neet Save WhatsApp Report

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Answer: 4. \(10x\,(kcal\,m^{-2})\,yr^{-1}\)

Key idea: the energy a trophic level can pass on is its net productivity; about 10 percent of it is stored by the next level (10 percent law).

Producers: NPP \(=100x\). This is the energy available to the second level, so the second level's GPP \(\approx100x\) (intake).
Second level keeps about 10 percent: NPP \(\approx10x\).
That \(10x\) is what is passed to the third level, so the GPP of the third level \(=10x\).

The answer is option 4, \(10x\), matching the official key. Honestly, the wording of 'GPP of a consumer' is loose, and counting differently gives \(x\).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is100x (kcal m^-2) yr^-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

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