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.