The practice of deliberately using microorganisms to help clean up polluted environments (soil, water, sediments) is called: (Choose the most accurate term for this applied environmental biotechnology.)

Introduction:
Microbes can transform, immobilize, or mineralize contaminants. This question assesses your knowledge of the umbrella term for deploying such biological processes in situ or ex situ to clean environments.

Given Data / Assumptions:

• Targets include hydrocarbons, solvents, pesticides, and some heavy metals (via valence changes/immobilization).
• Approaches: natural attenuation, biostimulation (nutrients/electron acceptors), and bioaugmentation (microbial addition).
• Success depends on geochemistry, bioavailability, and redox conditions.

Concept / Approach:
Bioremediation harnesses microbial metabolism to reduce contaminant mass/toxicity. Aerobic and anaerobic pathways are selected based on contaminant class (e.g., aerobic for petroleum hydrocarbons; anaerobic reductive dechlorination for chlorinated ethenes).

Step-by-Step Solution:
Identify the context: environmental cleanup via biological means. Match definitions: “bioremediation” is the precise term. Eliminate unrelated processes (food/medical or genetic delivery). Select the option that explicitly names the cleanup practice.

Verification / Alternative check:
Case studies of oil spill recovery and groundwater chlorinated solvent treatment demonstrate robust microbial-based remedies labeled under bioremediation.

Why Other Options Are Wrong:

• Pasteurization: Heat treatment for foods/liquids; not environmental cleanup.
• Fermentation: Industrial production process; not necessarily for pollutant removal.
• Biolistics: Gene delivery via particle bombardment, not remediation.

Common Pitfalls:
Confusing fermentation or composting with the broader, site-specific strategies involved in bioremediation.

Final Answer:
bioremediation is the correct term.