Asingle-celled organism, found in an extreme environment, would likely be classified in what kingdom?

That would be an archaebacteria.

Archaebacteria's are single celled organisms that can be found in extreme environments such as hot springs.

Hope this helps :)

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate