Science (086) — CBSE Class 10 board question

The materials which cannot be broken down by biological processes are called non-biodegradable substances.

Two ways they harm ecosystem components:

1. They persist in the environment for a long time and may harm various members of the ecosystem.
2. They undergo biological magnification — their concentration increases at each trophic level, becoming most harmful to organisms at the top of the food chain.

Source: Our Environment, Section 13.2.2

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The term "non-biodegradable" must be stated clearly — this alone fetches 1 mark. The second mark is for two harms. The passage explicitly states they "persist for a long time" or "harm various members of the ecosystem." Biological magnification (concentration increasing up the food chain) is the classic second point examiners expect. Avoid vague answers like "they pollute" — be specific.