Class XII · Biology practice

Ecosystem PYQs

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19 questions in this collection · Page 2 of 2

Question 11 of 19
🟢 NEET (Oct)2020 📘 CLASS XII

Ecosystem

The rate of decomposition is faster in the ecosystem due to following factors except:
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Question 12 of 19
🟢 NEET (Oct)2020 📘 CLASS XII

Ecosystem

Which of the following statements is incorrect regarding the phosphorus cycle?
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Question 13 of 19
🟢 NEET 2019 📘 CLASS XII

Ecosystem

Which of the following ecological pyramids is generally inverted?
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Question 14 of 19
🟢 NEET 2024 📘 CLASS XII

Ecosystem

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100x(kcalm–2)yr–1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?
NCERT Page No.206, (Topic-12.2 PRODUCTIVITY)
Question 15 of 19
🟢 Re NEET 2026 📘 CLASS XII

Ecosystem

Which of the following are primary consumers in a food chain?
Primary consumers feed directly on producers and are herbivores.
Question 16 of 19
🟢 Re NEET 2026 📘 CLASS XII

Ecosystem

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 10% law.

Choose the correct answer from the options given below:
Energy flow is unidirectional, the pyramid of energy is always upright, and only about 10% of energy is transferred from one trophic level to the next.
Question 17 of 19
🟢 NEET 2026 📘 CLASS XII

Ecosystem

Match List-I with List-II:

List-IList-II
A. DecompositionI. Accumulation of dark coloured amorphous colloidal substance
B. DetritusII. Release of inorganic nutrients by the activity of microbes in soil
C. MineralisationIII. Breaking down of complex organic matter into simpler substances
D. HumificationIV. Dead remains of plants and animals including faecal matter
Decomposition breaks down detritus. Detritus consists of dead organic matter. Mineralisation releases inorganic nutrients. Humification forms dark-coloured humus.
Question 18 of 19
🟢 NEET 2026 📘 CLASS XII

Ecosystem

Match List-I with List-II:

List-IList-II
A. ProductivityI. Gross primary productivity minus respiration losses
B. Net primary productivityII. Rate of formation of new organic matter by consumers
C. Gross primary productivityIII. Rate of biomass production
D. Secondary productivityIV. Rate of production of organic matter during photosynthesis
Productivity is the rate of biomass production. Net primary productivity equals GPP minus respiration losses. Gross primary productivity is the rate of photosynthesis, while secondary productivity is the rate of biomass formation by consumers.
Question 19 of 19
🟢 NEET 2026 📘 CLASS XII

Ecosystem

Ecological pyramids represent the relationship between the organisms at different trophic levels and they are generally inverted for:
In aquatic ecosystems, producer biomass is lower than consumer biomass at any given time, resulting in an inverted biomass pyramid.
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