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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] medium thorough-understanding
Which of the following best explains why decomposers are essential for the continuity of any ecosystem? (A) They produce food from inorganic substances using sunlight. (B) They return complex organic compounds back to simple inorganic substances that producers can reuse. (C) They transfer energy from one consumer to the next without any loss. (D) They regulate the population of herbivores by feeding on them.
  1. A They produce food from inorganic substances using sunlight.
  2. B They return complex organic compounds back to simple inorganic substances that producers can reuse.
  3. C They transfer energy from one consumer to the next without any loss.
  4. D They regulate the population of herbivores by feeding on them.
Generated by claude-sonnet-4-6 · 2026-06-26 00:58 · grounding rag
Model Answer

(B) They return complex organic compounds back to simple inorganic substances that producers can reuse.

Explanation

Decomposers (like bacteria and fungi) break down dead organic matter into simple inorganic nutrients, which are then absorbed by producers (plants) to restart the cycle. Without them, nutrients would remain locked in dead matter and the ecosystem would collapse. Option A describes producers, C is incorrect (energy is always lost), and D describes predators.

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.