Answer:Methanogens are a group of microorganisms that produce methane gas as a byproduct of their metabolism. They belong to the domain Archaea and are typically found in environments without oxygen, such as wetlands, the guts of ruminant animals (like cows), and sewage treatment plants. Methanogens play an important role in breaking down organic matter in anaerobic conditions and are key contributors to the natural production of methane, a greenhouse gas.