the hard, variously colored, calcareous skeleton secreted by certain marine polyps. 2. such skeletons collectively, forming reefs, islands, etc. 3. the solitary or colonial polyp that secretes this calcareous skeleton.
There are three major known groups of Archaebacteria: methanogens, halophiles, and thermophiles. The methanogens are anaerobic bacteria that produce methane. They are found in sewage treatment plants, bogs, and the intestinal tracts of ruminants.
Archaeabacteria is a kingdom in the domain Archaea, and Eubacteria is a kingdom in the domain Bacteria. Both kingdoms contain bacteria that are prokaryotic, unicellular, and a â¦ utotrophs or heterotrophs.