Bacterial decay of organic matter releases methane

Steps:

• Identify the process: Bacterial decay of vegetable matter involves anaerobic decomposition of organic material.
• Recall gas production: Anaerobic bacteria break down cellulose and other compounds, producing biogas.
• Determine primary gas: The main component of biogas from this decay is methane (CH4).
• Link to pollutants: Methane is a greenhouse gas and air pollutant from natural sources like wetlands.

Why B is correct:

• Methane forms via methanogenesis, where bacteria convert CO2 and H2 (or acetate) into CH4 during anaerobic digestion of organic matter.

Why the others are wrong:

• A: Carbon monoxide arises from incomplete combustion, not bacterial decay.
• C: Nitrogen dioxide comes from high-temperature combustion or lightning, not organic decay.
• D: Sulphur dioxide results from burning fossil fuels or volcanic activity, not vegetable matter breakdown.

Final answer: B