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 biology, a phylum (/ËfaÉªlÉm/ ; plural: phyla) is a taxonomic rank below kingdom and above class. Traditionally, in botany the term division was used instead of phylum, although from 1993 the International Code of Nomenclature for algae, fungi, and plants accepted the designation phylum.The kingdom Animalia contains approximately 35 phyla, Plantae contains 12, and Fungi contains 7.raditionally, in botany the term division was used instead of phylum, although from 1993 the International Code of Nomenclature for algae, fungi, and plants accepted the designation phylum. The kingdom Animalia contains approximately 35 phyla, Plantae contains 12, and Fungi contains 7.