Definition of a Tangent Plane We all have and intuitive idea of what the tangent plane to a point on a given surface should be. It is the plane that goes through that point and that it is tangent to the surface at that point. Suppose. z = f(x,y) is a smooth surface above the xy-plane (see the picture below).
The two prokaryotic domains (or empires),  Bacteria  (or  Eubacteria ) and  Archaea  (or  Archaeobacteria ), are subdivided into 35 phyla (or divisions): 30 phyla in the domain  Bacteria , and 5 phyla in the domain  Archaea .
Meronyms (parts of eubacteria): flagellum (a lash-like appendage used for locomotion (e.g., in sperm cells and some bacteria and protozoa)) Hyponyms (each of the following is a kind of eubacteria): B; bacillus (aerobic rod-shaped spore-producing bacterium; often occurring in chainlike formations; found primarily in soil) corynebacterium (any species of the genus Corynebacterium) listeria (any species of the genus Listeria)