Answer:
The correct answer will be options-
1. Methanogens
2. Halophiles
3. Thermoacidophiles
Explanation:
The unicellular organisms of the domain Archaea differ from the eubacteria as they contain the ether-linked lipids in their cell membrane instead of the ester-linked membrane and lacks peptidoglycan in their cell wall.
This forms a continuous layer of the membrane which provides adaptation to these bacteria to survive in the extreme environments.
In the given question, the organisms which represent the Archaea are the halophiles which live in saline conditions, thermoacidophiles which survive in extreme acidic hot conditions nad the methanogens which survive in the methane gas containing conditions.
Thus, the selected options are correct.
