What are methanogens ? How do they help to generate biogas ?

Explanation

### Step-by-Step Solution:

1. **Definition of Methanogens**:
- Methanogens are a specific group of microorganisms that produce methane as a metabolic byproduct. They belong to the domain Archaea and thrive in anaerobic (oxygen-free) environments.

2. **Anaerobic Conditions**:
- Methanogens operate under anaerobic conditions, meaning they do not require oxygen to survive. Instead, they utilize other substances to carry out their metabolic processes.

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