Science (086) — CBSE Class 10 board question

Decomposers are microorganisms (mainly bacteria and fungi) that break down the complex organic matter of dead plants and animals into simple inorganic substances.

Examples: Bacteria and fungi (e.g., Rhizopus, mushrooms).

Role in maintaining balance:

1. They return nutrients back to the soil, making them available for plants (producers) to reuse, thus ensuring the continuous cycling of materials in the ecosystem.
2. They help in the decomposition of dead organic matter, preventing its accumulation and keeping the environment clean.

Source: Our Environment, Chapter 13

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• Examiners expect a clear definition (1 mark), two examples (½ + ½ mark), and two distinct points on balancing the ecosystem (1 mark).
• Key phrases to include: "break down complex organic matter," "simple inorganic substances," "nutrient cycling/recycling."
• Bacteria and fungi are the standard examples accepted; naming a specific organism like Rhizopus is a bonus but not required.
• Do not confuse decomposers with consumers — decomposers act on dead organic matter.