Final answer:
Archaea, previously known as Archaebacteria, live everywhere, including extreme environments. They can be autotrophic or heterotrophic, and their metabolism produces various compounds.
Step-by-step explanation:
Archaebacteria, now more commonly referred to as Archaea, are found in many diverse environments across the globe, including some of the planet's most extreme habitats. Although they were first discovered in extreme environments such as hot springs and salt lakes, these prokaryotes inhabit a wide range of ecosystems.
As with their bacterial counterparts, Archaea are unicellular, lack a nucleus, and are distinct from eukaryotes; however, they have unique structural differences from Bacteria, particularly in their cell wall composition and membrane lipids. Archaea play various roles in their ecosystems, with dietary habits that can be quite diverse.
Some Archaea species are autotrophs, able to produce their food through chemosynthesis or photosynthesis, while others are heterotrophs, consuming organic compounds produced by other living organisms. Depending on the species, Archaea can produce methane, carbon dioxide, or even sulfur compounds.