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Ecosystem — NEET Biology MCQs

30 questions written by hand against the NCERT chapter. Every wrong option is explained, not just the right one.

30questions
10/14/6easy / medium / hard
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Sample questions from this chapter

Vertical distribution of species into forest layers is called
  1. stratification ✓
  2. mineralisation
  3. productivity
  4. fragmentation
Answer: A. Trees, shrubs and herbs occupy different vertical strata, creating a characteristic physical structure in a forest ecosystem.
Why not B: Mineralisation releases inorganic nutrients from organic matter.
Why not C: Productivity is the rate of biomass production.
Why not D: Fragmentation breaks detritus into smaller particles.
Why is productivity expressed per unit area per unit time, unlike production alone?
  1. Productivity measures the rate of biomass formation and permits ecosystem comparisons ✓
  2. Productivity is the total producer biomass present at one sampling time
  3. Production always measures consumer number
  4. Time units convert biomass into heat
Answer: A. An amount of organic matter becomes a productivity value when normalised to both space and time, such as g m^-2 yr^-1.
Why not B: Biomass present at one time is standing crop; productivity measures how rapidly new biomass or organic matter is formed.
Why not C: Consumer organic-matter formation is secondary productivity, not the definition of production.
Why not D: Adding a time dimension describes rate; it does not convert matter into heat.
Two ecosystems have equal GPP, but forest X has higher plant respiration than forest Y. Which prediction follows?
  1. X has lower NPP and therefore less newly produced biomass available to heterotrophs ✓
  2. X has higher NPP because respiration creates biomass
  3. Both have equal NPP because GPP alone determines it
  4. Y has lower NPP because its lower respiration returns less carbon dioxide for photosynthesis
Answer: A. With the same gross fixation, a larger respiratory cost leaves a smaller net balance for plant growth and transfer through grazing or detrital routes.
Why not B: Respiration consumes part of gross production.
Why not C: NPP depends on the difference between GPP and plant respiration.
Why not D: GPP is already stated to be equal; within NPP = GPP - R, lower plant respiration in Y leaves more net biomass rather than less.

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Other NEET Biology chapters

The Living WorldBiological ClassificationPlant KingdomAnimal KingdomMorphology of Flowering PlantsAnatomy of Flowering Plants

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Questions

How many NEET questions are there on Ecosystem?

This chapter test has 30 questions — 10 easy, 14 medium and 6 hard — all written against the NCERT Class 12 chapter.

Is this NEET Biology chapter test free?

Yes. Every chapter test is free with no login, and you get your all-India rank on every one. Nothing on the site is on sale right now.

Do the questions explain the wrong options?

Yes — every distractor carries its own explanation naming the specific misconception that makes a student pick it. That is the part most question banks skip, and it is the part that changes your next attempt.