1. (b) Biodegradable substances can be broken down into simpler harmless substances in nature by microorganisms whereas non-biodegradable substances cannot be broken down into simpler harmless substances in nature.

    (b) Biodegradable substances can be broken down into simpler harmless substances in nature by microorganisms whereas non-biodegradable substances cannot be broken down into simpler harmless substances in nature.

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  2. (c) they alone have the capacity to synthesise food using sunlight

    (c) they alone have the capacity to synthesise food using sunlight

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