What is biogas? Name the principal organism involved in its production.

Explanation

### Step-by-Step Solution

1. **Definition of Biogas**:
- Biogas is defined as a mixture of gases that is produced through the anaerobic decomposition of organic matter. This organic matter can include animal dung, plant material, and other biodegradable waste.

2. **Components of Biogas**:
- The primary components of biogas include:
- Methane (CH₄)
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