Methanogens usually require Choose one: A. acidic conditions. B. methane as a substrate. C. high temperatures. D. association with bacterial species.

D. association with bacterial species.

Explanation:

Methanogens -

These are the organisms , that falls under the category of the prokaryotes , in the domain archaea .

Methanogens are a type of microorganism , which is capable to produce methane as one of the by product during a hypoxic condition .

These organisms are found in the wetland , inside the digestive system of the humans and animals .

They have an important space for the treatment of the anaerobic wastewater .

Hence , from the question ,

The correct option is d.