Editing Carbon group (section)

==Biological role==
Carbon is a key element to all known life. It is in all organic compounds, for example, [[DNA]], [[steroid]]s, and [[protein]]s.<ref name = "The Elements">{{Citation|last = Gray|first = Theodore|title = The Elements|year = 2011}}</ref> Carbon's importance to life is primarily due to its ability to form numerous bonds with other elements.<ref name="The Disappearing Spoon">{{Citation|last = Kean|first = Sam|title = The Disappearing Spoon|year = 2011}}</ref> There are 16 kilograms of carbon in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

[[Silicon-based life]]'s feasibility is commonly discussed. However, it is less able than carbon to form elaborate rings and chains.<ref name = "The Elements"/> Silicon in the form of [[silicon dioxide]] is used by [[diatoms]] and [[sea sponges]] to form their [[cell walls]] and [[skeletons]]. Silicon is essential for [[bone]] growth in chickens and rats and may also be essential in humans. Humans consume on average between 20 and 1200 [[milligrams]] of silicon per day, mostly from [[cereals]]. There is 1 gram of silicon in a typical 70-kilogram human.<ref name = "Nature's Building Blocks">{{Citation|last = Emsley|first = John|title = Nature's Building Blocks|year = 2011}}</ref>

A biological role for germanium is not known, although it does stimulate [[metabolism]]. In 1980, germanium was reported by [[Kazuhiko Asai]] to benefit health, but the claim has not been proven. Some plants take up germanium from the soil in the form of [[germanium oxide]].{{clarify|date=August 2019|reason=Ge(II) or Ge(IV)?}} These plants, which include [[Food grain|grain]]s and [[vegetables]] contain roughly 0.05 parts per million of germanium. The estimated human intake of germanium is 1 milligram per day. There are 5 milligrams of germanium in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Tin has been shown to be essential for proper growth in rats, but there is, as of 2013, no evidence to indicate that humans need tin in their diet. Plants do not require tin. However, plants do collect tin in their [[root]]s. [[Wheat]] and [[maize]] contain 7 and 3 parts per million respectively. However, the level of tin in plants can reach 2000 parts per million if the plants are near a tin [[smelter]]. On average, humans consume 0.3 milligrams of tin per day. There are 30 milligrams of tin in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Lead has no known biological role, and is in fact highly [[toxic]], but some [[microbes]] are able to survive in lead-contaminated environments. Some plants, such as [[cucumber]]s contain up to tens of parts per million of lead. There are 120 milligrams of lead in a typical 70-kilogram human.<ref name="Nature's Building Blocks"/>

Flerovium has no biological role and instead is found and made only in particle accelerators.

===Toxicity===
Elemental carbon is not generally toxic, but many of its compounds are, such as [[carbon monoxide]] and [[hydrogen cyanide]]. However, carbon dust can be dangerous because it lodges in the lungs in a manner similar to [[asbestos]].<ref name = "Nature's Building Blocks"/>

Silicon minerals are not typically poisonous. However, silicon dioxide dust, such as that emitted by [[volcanoes]] can cause adverse health effects if it enters the lungs.<ref name = "The Disappearing Spoon"/>

Germanium can interfere with such [[enzymes]] as [[lactate dehydrogenase]] and [[alcohol dehydrogenase]]. Organic germanium compounds are more toxic than inorganic germanium compounds. Germanium has a low degree of [[mouth|oral]] toxicity in animals. Severe germanium poisoning can cause death by [[respiratory paralysis]].<ref>{{Citation|url=http://www.food.gov.uk/multimedia/pdfs/evm_germanium.pdf%20 |title=Risk Assessment |year=2003 |access-date=January 19, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120112060340/http://www.food.gov.uk/multimedia/pdfs/evm_germanium.pdf |archive-date=January 12, 2012 }}</ref>

Some tin compounds are toxic to ingest, but most inorganic compounds of tin are considered nontoxic. Organic tin compounds, such as [[trimethyltin]] and [[triethyltin]] are highly toxic, and can disrupt metabolic processes inside cells.<ref name="Nature's Building Blocks"/>

Lead and its compounds, such as [[lead acetate]]s are highly toxic. [[Lead poisoning]] can cause [[headaches]], stomach pain, [[constipation]], and [[gout]].<ref name = "Nature's Building Blocks"/>

Flerovium is too radioactive to test if it's toxic or not although its high radioactivity alone would be toxic.