What is a group of species that have similar to bacteria?

A group of species that are similar to bacteria includes archaea, which are single-celled microorganisms that often thrive in extreme environments. Both bacteria and archaea are prokaryotes, meaning they lack a nucleus and membrane-bound organelles. While they share some similarities in structure and function, archaea have distinct biochemical pathways and genetic sequences that differentiate them from bacteria. Together, they represent two of the three domains of life, with eukaryotes being the third.