Definition
Archaeobacteria is an older, less accurate term for what we now call Archaea. These are single-celled organisms lacking a nucleus, but they're *not* bacteria. Think of them as imposters in the bacteria world! 🕵️♀️ They often live in extreme environments like hot springs, salt lakes, and even in animal guts. Scientists discovered they're genetically distinct from bacteria and deserve their own domain. They're crucial for various ecological processes, like methane production.