Biology
You are a process, not a thing
Yes: skin, blood, gut lining, and even your skeleton are torn down and rebuilt from new material on a running schedule, your bones taking roughly a decade. Scientists proved this using carbon-14 left over from 1950s-60s nuclear bomb tests, absorbed into your DNA, to literally date the age of your cells.
Sources & further reading
Cell / PubMed, National Library of Medicine (NIH)Retrospective Birth Dating of Cells in HumansThe core study: scientists used leftover carbon-14 from 1950s-60s nuclear bomb tests to show most of your cells get replaced, but neurons in your visual cortex don't.Karolinska InstitutetNew neurons generated in the hippocampus of adult humansThe follow-up finding: unlike most of the brain, the hippocampus keeps making new neurons throughout adult life.
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