They are dissimilar enough to both prokaryotes and eukaryotes that they became their own third domain on the tree of life. And they became ... that the three domain model was made using a highly ...

The three-domain tree continued ... to build a tree of life has to rely on a model for how DNA evolves–whether some sites are more prone to mutation than others, for example.

Archaea, hardy single-celled organisms that form the third domain at the top of the universal tree of life ... the two other domains of life in the widely accepted model are the bacteria and ...