State economically important uses of methanogens.

Explanation

**Step-by-Step Solution:**

1. **Definition of Methanogens**: Begin by defining what methanogens are. Methanogens are a group of microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are primarily found in the intestines of ruminant animals and in anaerobic environments.

2. **Role in Digestion**: Explain their role in the digestive systems of ruminant animals. Methanogens help in the digestion of cellulose, which is a major component of plant cell walls. This process is crucial for the breakdown of complex carbohydrates into simpler compounds that can be absorbed by the host animal.

3. **Production of Methane**: Highlight the significance of methane production. Methanogens are responsible for the production of methane gas, which is a form of biogas. This methane is generated during the digestion process in the gut of ruminants.

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