Organisms that live in exceptionally harsh conditions such as hydrothermal vents, similar to what was found in early Earth's primitive conditions, are classified in what domain?

A. Archaea

B. Bacteria

C. Eukarya

D. Prokary

simple. the answer is A. archaea because they can be found not living, but thriving in extreme conditions such as hydrothermal vents.

B. Bacteria live in conditions that are not as extreme as archaea but are barely able to inhabit the extreme conditions that archaea thrive in.

C. Eukarya is the domain of Prokaryotic organisms that make up animals, plants, fungi, and other living organisms

D. Prokay is what any single celled organism is called without bothering to classify it.