Register for FREE to remove ads and unlock more features! Learn more. The renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance . This system proceeds through several steps to produce angiotensin II, which acts to stabilize blood pressure and volume.
A fish is any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits.Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups.ish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event. Early fish from the fossil record are represented by a group of small, jawless, armored fish known as Ostracoderms. Jawless fish lineages are mostly extinct.
In general, common examples of multicellular organisms are the following: Animals, plants, fungi, human-beings, and as mentioned, a specialized type of parasitic animal called Myxozoa. 1. Unicellular organisms have one cell, while multicellular organisms are composed of many different types of cells.2. Unicellular organisms are mostly prokaryotes, while multicellular organisms are generally classified as eukaryotes. 3.enerally, unicellular organisms fall under the umbrella of the prokaryotes, or prokaryotic entities. They are termed as prokaryotes because they are not that specialized, unlike the more complex eukaryotes. Unicellular organisms and the prokaryotes do not have the structure called the cell nuclei.