This test is only done in combination with the initial screening test. HIV RNA tests: The HIV RNA is different than all human RNA, and tests have been developed to detect HIV RNA in a person's blood. This uses a type of test called a polymerase chain reaction (PCR).
Taxonomy refers to the official classifications of plants or animals according to accepted scientific standards and norms. As a group, sharks belong to the superorder called Selachimorpha. They are in the Chondrichthyes class (along with Chimaeras) under the subclass Elasmobranchii.This subclass is also where rays and skates fall and some sharks are thought to be very closely related to certain ray species (even more so than to other sharks, in fact). Selachimorpha is split into Galea and Squalea.The Galea group comprises:his subclass is also where rays and skates fall and some sharks are thought to be very closely related to certain ray species (even more so than to other sharks, in fact). Selachimorpha is split into Galea and Squalea. The Galea group comprises:
The best-known taxonomic ranks are, in order: life, domain, kingdom, phylum, class, order, family, genus, and species. This assignment to a genus is not immutable; later a different (or the same) taxonomist may assign it to a different genus, in which case the name will also change.ristotle used the words genus and species to mean generic and specific categories. Aristotle and other pre-Darwinian scientists took the species to be distinct and unchanging, with an  essence , like the chemical elements.