Answer:
Archaea
Step-by-step explanation:
Archaea are prokaryotes, which means they lack a nucleus. Many Archaea are extremophiles, organisms that live in extreme conditions, which give us another hint. But most importantly, a unique characteristic of Archaea is the presence of ether linkages in the lipids of their cytoplasmic membranes. This distinguishes archaea from eukaryotes and most bacteria.