Which statement best defines bioremediation?

• A. Use of living organisms to degrade environmental pollutants; genetic modification to improve pathways.
• B. Chemical treatment with strong oxidants to break down pollutants.
• C. Physical removal of contaminated soil.
• D. Use of non-living catalysts to neutralize toxins.

Answer: (A)

Bioremediation relies on living organisms to break down environmental pollutants. Microbes metabolize contaminants, converting them into less harmful substances such as carbon dioxide, water, or biomass. The note about genetic modification to improve pathways highlights how scientists can enhance enzyme activity or metabolic routes to speed up degradation, though many real-world cases use native organisms as well. The other described methods—chemical oxidation, physical removal, or using non-living catalysts—don’t involve biological metabolism, so they’re not bioremediation.