AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Biodegradable substances are broken down by biological processes (microorganisms). Example: vegetable peels.
Non-biodegradable substances are not broken down biologically and persist in the environment. Example: plastic.
Source: Our Environment, Section 13.2.2
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Since this is a 1-mark question, examiners expect both definitions in one or two compact lines with one example each. No elaboration needed. Key terms to use: "biological processes / microorganisms" for biodegradable, and "not broken down / persist" for non-biodegradable. Common examples: biodegradable — fruit peels, food waste; non-biodegradable — plastic, glass, DDT. Avoid writing lengthy paragraphs.