over five billion species, are extinct.

Earth is the only celestial body known to harbor life forms. No form of extraterrestrial life has yet been discovered.

Archaea

* Archaea – a domain of single-celled microrganisms, morphologically similar to bacteria, but they possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably the enzymes involved in transcription and translation.

1.Previous
3.Next