Archaea are classified into three groups depending on their metabolism. Cite these three groups and define each one briefly

There are three classes of Archaea are Methanogens, Halophils and Thermo acidophills

Explanation:

Methanogens : They produce methane gas a waste product of their digestion or process of making energy

Halophiles: They live in salty environments

Thermoacidophilles: They live in hot acidic terrestrial environments. They are Crenarchaeota belonging to the Acidilobales and the Sulfolobales.