- A Methane and oxygen
- B Methane, CO2, and H2S
- C Hydrogen and nitrogen
- D Carbon monoxide and methane
Correct answer: B. Methane, CO2, and H2S
Explanation: Biogas produced by anaerobic digestion of sewage sludge contains methane (CH4), carbon dioxide (CO2), and hydrogen sulfide (H2S).
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers