The methanogens, producers of methane gas, require environments that:

• A. contain high concentrations of oxygen
• B. are highly acidic
• C. are strictly anaerobic
• D. are exposed to direct sunlight

Answer: (C)

Verified step by step guidance

1. Understand the nature of methanogens: Methanogens are a group of Archaea that produce methane as a metabolic byproduct in anoxic (oxygen-free) conditions.
2. Recall that methanogens are strictly anaerobic organisms, meaning they cannot survive in the presence of oxygen because oxygen is toxic to their metabolic processes.
3. Evaluate the given options by comparing them to the known environmental requirements of methanogens: high oxygen concentration and exposure to sunlight are unfavorable, and high acidity is not a defining requirement.
4. Identify that the correct environmental condition for methanogens is an anaerobic environment, where oxygen is absent or at very low levels.
5. Conclude that the statement 'are strictly anaerobic' correctly describes the environment required by methanogens to produce methane gas.