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Selenium, which is an essential element for animals and prokaryotes and is a beneficial element for many plants, is the least-common of all the elements essential to life. [3] [63] Selenium acts as the catalytic center of several antioxidant enzymes, such as glutathione peroxidase, [11] and plays a wide variety of other biological roles.
See also: Carbon-based life: Fossil fuels: coal, methane and petroleum Textile industry: cellulose Metallurgy: alloys, especially carbon steel 7: N: Nitrogen 2: 15: Bacteria and archaea: nitrogen fixation by diazotrophs All forms of life on Earth: essential component of amino acids and of nucleic acids Earth's atmosphere, soil, and life forms ...
This is the longest known half-life among all radionuclides [20] and is about 160 trillion (10 12) times the age of the known universe. A further 31 artificial radioisotopes of tellurium are known, with atomic masses ranging from 104 to 142 and with half-lives of 19 days or less.
All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. [1] All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace ...
Sulfur is an essential element for all life, almost always in the form of organosulfur compounds or metal sulfides. Amino acids (two proteinogenic: cysteine and methionine, and many other non-coded: cystine, taurine, etc.) and two vitamins (biotin and thiamine) are organosulfur compounds crucial for life.
Aristotle (384 BCE–322 BCE) was the first to put the conception on a sound philosophical basis, which he did in his natural philosophy, especially in Physics book I. [71] He adopted as reasonable suppositions the four Empedoclean elements, but added a fifth, aether. Nevertheless, these elements are not basic in Aristotle's mind.
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Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. . "CHON" stands for carbon, hydrogen, oxygen, and nitrogen, which together make up more than 95 percent of the mass of biological system