Death

== Senescence ==
{{main|Senescence}}
[[File:Kameldornbaum Sossusvlei.jpg|thumb|Dead [[Vachellia erioloba|camel thorn tree]] within [[Sossusvlei]]]]

Senescence refers to a scenario when a living being can survive all calamities but eventually dies due to causes relating to old age. Conversely, premature death can refer to a death that occurs before old age arrives, for example, human death before a person reaches the age of 75.<ref>{{Cite web |title=The top five causes of premature death |url=https://familyserviceshub.havering.gov.uk/kb5/havering/directory/advice.page?id=6ShWTMD1aSU |access-date=2023-08-15 |website=familyserviceshub.havering.gov.uk |archive-date=21 September 2021 |archive-url=https://web.archive.org/web/20210921235905/https://familyserviceshub.havering.gov.uk/kb5/havering/directory/advice.page?id=6ShWTMD1aSU |url-status=live }}</ref> Animal and plant cells normally reproduce and function during the whole period of natural existence, but the aging process derives from the deterioration of cellular activity and the ruination of regular functioning. The aptitude of cells for gradual deterioration and mortality means that cells are naturally sentenced to stable and long-term loss of living capacities, even despite continuing metabolic reactions and viability. In the United Kingdom, for example, nine out of ten of all the deaths that occur daily relates to senescence, while around the world, it accounts for two-thirds of 150,000 deaths that take place daily.<ref>{{Cite book |last1=Hayflick |first1=Loeonard |url=https://search.issuelab.org/resource/has-anyone-ever-died-of-old-age.html |title=Has Anyone Ever Died of Old Age? |last2=Moody |first2=Harry R. |publisher=Internation Longevity Center–USA |date=2003 |access-date=16 February 2023 |archive-date=6 March 2023 |archive-url=https://web.archive.org/web/20230306150733/https://search.issuelab.org/resource/has-anyone-ever-died-of-old-age.html |url-status=live }}</ref>

Almost all animals who survive external hazards to their biological functioning eventually die from [[Senescence|biological aging]], known in life sciences as "senescence." Some organisms experience [[negligible senescence]], even exhibiting [[biological immortality]]. These include the jellyfish ''[[Turritopsis dohrnii]]'',<ref>{{cite web|url=http://www.jellyfishfacts.net/turritopsis-nutricula-immortal-jellyfish.html |title=Turritopsis nutricula (Immortal jellyfish) |publisher=Jellyfishfacts.net |access-date=18 January 2014 |archive-url=https://web.archive.org/web/20161013163459/http://www.jellyfishfacts.net/turritopsis-nutricula-immortal-jellyfish.html |archive-date=13 October 2016 }}</ref> the [[Hydra (genus)|hydra]], and the [[planarian]]. Unnatural causes of death include suicide and [[predation]]. Of all causes, roughly 150,000 people die around the world each day.<ref name="doi10.2202/1941-6008.1011">{{cite journal|last=Aubrey D.N.J |first=de Grey |author-link=Aubrey de Grey |title=Life Span Extension Research and Public Debate: Societal Considerations |journal=Studies in Ethics, Law, and Technology |volume=1 |issue=1, Article 5 |year=2007 |url=http://www.sens.org/files/pdf/ENHANCE-PP.pdf |doi=10.2202/1941-6008.1011 |access-date=20 March 2009 |archive-url=https://web.archive.org/web/20161013163622/http://www.sens.org/files/pdf/ENHANCE-PP.pdf |archive-date=13 October 2016|citeseerx=10.1.1.395.745 |s2cid=201101995 |quote=roughly 150,000 deaths that occur each day across the globe}}</ref> Of these, two-thirds die directly or indirectly due to senescence, but in industrialized countries – such as the United States, the United Kingdom, and Germany – the rate approaches 90% (i.e., nearly nine out of ten of all deaths are related to senescence).<ref name="doi10.2202/1941-6008.1011" />

[[Physiological]] death is now seen as a process, more than an event: conditions once considered indicative of death are now reversible.<ref>{{cite web|last=Crippen |first=David |website=Scientific American Surgery, Critical Care, April 2005 |url=http://www.sciamsurgery.com/sciamsurgery/institutional/payPerAdd.action?chapterId=part08_ch10 |archive-url=https://web.archive.org/web/20060624132446/http://www.acssurgery.com/abstracts/acs/acs0812.htm |archive-date=24 June 2006 |title=Brain Failure and Brain Death |access-date=9 January 2007}}</ref> Where in the process, a dividing line is drawn between life and death depends on factors beyond the presence or absence of [[vital signs]]. In general, [[clinical death]] is neither necessary nor sufficient for a determination of [[legal death]]. A patient with working [[human heart|heart]] and [[human lung|lungs]] determined to be [[brain death|brain dead]] can be pronounced legally dead without clinical death occurring.<ref>{{Cite journal |last1=Burkle |first1=Christopher M. |last2=Sharp |first2=Richard R. |last3=Wijdicks |first3=Eelco F. |date=October 14, 2014 |title=Why brain death is considered death and why there should be no confusion |journal=Neurology |volume=83 |issue=16 |pages=1464–1469 |doi=10.1212/WNL.0000000000000883 |pmid=25217058 |pmc=4206160 }}</ref>