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 .
In return, these bacteria are provided with a comfortable environment and a consistent supply of nutrients by us. Other common groups of eubacteria are autotrophsâbacteria that can make their own food through photosynthesis. They have a chain-like structure and are commonly found in moist areas like lakes and ponds.