Q: Archaeans produce what kind of gas as a waste product?


Read this paragraph and choose the correct option from the provided answers:

Many archaeans live in close relationships with other organisms. For example, large numbers live inside animals, including humans. Unlike many bacteria, archaeans don't harm their hosts. None of them is known to cause human disease. Archaeans are more likely to help their hosts. For example, archaeans called methanogens live inside the gut of cows (see Figure below ). They help cows digest tough plant fibers made of cellulose. They produce methane gas as a waste product.

 Choices:

- sulfide

- carbon monoxide

- carbon dioxide

- methane


A:
methane