OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What does it indicate if a chemical is described as non-biodegradable?

1. It can be broken down quickly by microorganisms

2. It can remain in the environment for extended periods

3. It is safe to dispose of in landfills

4. It will decompose within a year

The correct answer is: It can remain in the environment for extended periods

When a chemical is described as non-biodegradable, it signifies that it is resistant to breakdown by natural processes, particularly those involving microorganisms. This means that it does not decompose easily and can persist in the environment for prolonged periods, leading to potential environmental harms such as pollution and accumulation in ecosystems. Biodegradable materials, on the other hand, can be quickly decomposed by the action of bacteria and other microorganisms, so options implying rapid breakdown or safety in disposal are not applicable. Non-biodegradable substances often require special handling for disposal, as they do not return to the natural cycle effectively. Therefore, the understanding that such substances remain intact within the environment for extensive time frames is key to addressing environmental sustainability issues.