Biogas is produced by

Options

A. aerobic breakdown of biomass
B. anaerobic breakdown of biomass
C. with the help of methanogenic bacteria
D. both (b) and (c)

Answer

### Step-by-Step Solution:

1. **Understanding Biogas**:
- Biogas is a type of biofuel that is primarily composed of methane (CH₄), along with carbon dioxide (CO₂) and small amounts of other gases such as hydrogen (H₂) and hydrogen sulfide (H₂S).

2. **Source of Biogas Production**:
- Biogas is produced through the breakdown of organic matter or biomass. This process can occur under two conditions: aerobic (with oxygen) and anaerobic (without oxygen).

3. **Role of Methanogenic Bacteria**:
- The production of biogas specifically occurs through the anaerobic breakdown of biomass. This process is facilitated by a specific group of microorganisms known as methanogenic bacteria. These bacteria belong to the category of Archaea and thrive in low-oxygen environments.

4. **Anaerobic Breakdown**:
- In anaerobic conditions, methanogenic bacteria decompose organic matter, leading to the release of biogas. This process is essential for the production of methane, which is the main component of biogas.

5. **Evaluating the Options**:
- The question provides several options regarding how biogas is produced:
- A) Aerobic breakdown of biomass (Incorrect)
- B) Anaerobic breakdown of biomass (Correct)
- C) Breakdown of biomass with the help of methanogenic bacteria (Correct)
- D) Both B and C (Correct)

6. **Conclusion**:
- Since both options B and C are correct, the final answer is option D: "Both B and C".