Define biodegradation and give an environmental example.

• A. Biodegradation is the breakdown of substances by living organisms; e.g., microbial decomposition of organic waste.
• B. Biodegradation is the chemical transformation of pollutants by sunlight.
• C. Biodegradation is the physical fragmentation of solids by wave action.
• D. Biodegradation creates new synthetic polymers in landfills.

Answer: (A)

Biodegradation is the breakdown of substances by living organisms, especially microorganisms like bacteria and fungi, that metabolize organic material into simpler compounds. In the environment, this process recycles organic waste and releases nutrients back into soil or water. An environmental example is microbial decomposition of organic waste such as food scraps or plant matter in a compost pile, where microbes break down the material into carbon dioxide, water, and biomass. The other descriptions refer to different processes: sunlight-driven changes are photodegradation, physical fragmentation is a form of physical weathering, and forming new synthetic polymers in landfills is not degradation at all.